R911172835_03_ALR_EN

Prévia do material em texto

Rexroth PSI 6xCx
The Drive & Control Company
Process regulation and monitoring for aluminum spot
welding
Edition 03Description of application
R911172835
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and Controls
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The data indicated below is intended to describe the
product. Should information on its use be provided,
such information represents application examples
and suggestions only. Catalog specifications shall
not be deemed as warranted quality. 
This information does not release the user from per­
forming his own assessments and verifications. 
Our products are subject to natural wear and aging.
© This manual is the exclusive property of Bosch
Rexroth AG, Germany also in the case of intellec­
tual property right applications.
Reproduction or distribution by any means subject to
our prior written permission.
An example configuration is shown on the cover
page. The delivered product may therefore deviate
from the picture.
Language version of the document: EN
Original language of the document: DE
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Contents
Contents 
1 Regarding this documentation 5. . . . . . . . . . . . . . . . 
1.1 Validity of this documentation 5. . . . . . . . . . . . . . . . . . . . . . . . . . . 
1.2 Additional documentation 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
1.3 Presentation of information 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
1.3.1 Safety instructions 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
1.3.2 Icons 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
1.3.3 Designations 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
1.3.4 Abbreviations 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
2 Safety instructions 9. . . . . . . . . . . . . . . . . . . . . . . . . . 
3 General information on damage to property and
products 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
4 Scope of delivery 13. . . . . . . . . . . . . . . . . . . . . . . . . . . 
5 General information on the „ALR license option“ 15. 
5.1 Functions and options 15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
5.2 Requirements 17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
5.3 Information on assembly and connection 17. . . . . . . . . . . . . . . . . 
5.3.1 Voltage tapping 20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
5.3.2 Parameterization of the force feedback 22. . . . . . . . . . . . . . . . . 
5.4 Activating/deactivating the option 24. . . . . . . . . . . . . . . . . . . . . . . . 
6 Basics 25. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
6.1 Interpretation of the force characteristics 26. . . . . . . . . . . . . . . . . 
6.2 Interpretation of the resistance curves 27. . . . . . . . . . . . . . . . . . . 
6.3 Welds with insulating materials 28. . . . . . . . . . . . . . . . . . . . . . . . . . 
6.4 Welds with expulsion 29. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
7 Commissioning of the process control 31. . . . . . . . . 
7.1 Basic requirements 31. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
7.2 Determining the basic welding parameters 31. . . . . . . . . . . . . . . . 
7.3 Generating reference curves 36. . . . . . . . . . . . . . . . . . . . . . . . . . . . 
7.3.1 Requirements 36. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
7.3.2 Defining the force curve as reference curve 37. . . . . . . . . . . . . 
7.3.3 Recording by recorder 40. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
7.4 Activating process control 48. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
7.4.1 Description of the most important process parameters 49. . . . 
7.4.2 Special features for activated process control 54. . . . . . . . . . . 
7.5 Deactivating the process control 55. . . . . . . . . . . . . . . . . . . . . . . . . 
8 Process monitoring parameters 59. . . . . . . . . . . . . . . 
8.1 Available parameters 59. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
8.2 Information on the use of monitoring variables 62. . . . . . . . . . . . 
8.3 Procedure for commissioning 64. . . . . . . . . . . . . . . . . . . . . . . . . . . 
8.4 Deactivating process monitoring 68. . . . . . . . . . . . . . . . . . . . . . . . . 
8.5 Dynamic tolerance band adjustment 71. . . . . . . . . . . . . . . . . . . . . 
8.5.1 Relevant parameters 71. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
8.5.2 Determination of the required parametrization 73. . . . . . . . . . . 
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Contents
9 For quick information 76. . . . . . . . . . . . . . . . . . . . . . . . 
9.1 Status of the process functionality 76. . . . . . . . . . . . . . . . . . . . . . . 
9.1.1 "Overview" topic, "Overview" tab 76. . . . . . . . . . . . . . . . . . . . . . . 
9.1.2 PSQ status display 77. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
9.2 Actual values determined for the last welding schedule 78. . . . . 
9.3 Curve characteristics of the last 64 welds of a timer 79. . . . . . . . 
9.4 Spot/expulsion overview 80. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
9.5 Display of the PSF, UIP and FQF process variables 81. . . . . . . 
9.6 UIR process overview 84. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
10 Q Stop (Quality Stop) 87. . . . . . . . . . . . . . . . . . . . . . . . 
10.1 Program-specific Q Stop 87. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
10.2 Component-specific Q Stop 88. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
10.3 Exceptions 88. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
10.4 Special spots 89. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
10.5 Configuration 89. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
11 Static gun resistance compensation 91. . . . . . . . . . . 
11.1 Setting of the gun resistance compensation 92. . . . . . . . . . . . . . 
11.2 Activating the gun resistance compensation 96. . . . . . . . . . . . . . 
11.3 Procedure after a gun replacement 96. . . . . . . . . . . . . . . . . . . . . . 
11.4 Special cases 99. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
12 List of tables 105. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
13 List of figures 107. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
14 Abbreviations 111. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
15 Index 115. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
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Regarding this documentation
1 Regarding this documentation
This chapter includes important information on the use of the docu­
mentation.
� Inform yourself about the product before you work with it!
1.1 Validity of this documentation
The present documentation
• applies to 
the „process regulation and monitoring for aluminum spot welding“
option (ALR license) of the PSI 6xxx weld timers
• is designed for 
planning, assembly personnel, operators, start-up, service techni­
cians, plant operators
• provides information about
• Electr. connection of the required sensors
• Process measurement, control, monitoring
• Activating and deactivating the „Process regulation and monitor­
ing for aluminum spot welding function“
1.2 Additionaldocumentation
Several documents are available for the product which are needed to­
gether for comprehensive information.
� Only start the product when you are at least familiar with and under­
stand the documents marked with �.
Table�1: Necessary and supplementary documents
Title Doc. no. Document type
� PSI 6xxx: Weld timer with medium-
frequency inverter
1070080028 Operating instruc­
tions
� PSI 6xxx.xxx xx: Weld timer with
medium-frequency inverter, type-
specific supplement
depending
on type
Operating instruc­
tions (type-specific
supplement)
� PSG 3xxx/6xxx: MF welding trans­
formers
1070087062 Operating instruc­
tions
BOS 6000 online help 1070086446 Reference
� PSI 6xxx: UI regulation and monit­
oring
1070087072 Description of ap­
plication
� PSI 6xCx: Process regulation and
monitoring for aluminum spot weld­
ing
R911172835 Description of ap­
plication
�: necessary document
For which product?
Target group?
Topics dealt with?
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Regarding this documentation
1.3 Presentation of information
We use uniform icons, terms and abbreviations in this documentation.
They will be explained in the following paragraphs.
1.3.1 Safety instructions
Safety instructions call your attention specifically to danger potentials or
risks.
We distinguish among the following places where safety instructions
may be required:
• Basic safety instructions:
They are related to general important matters and apply to the com­
plete documentation.
These safety instructions are provided in Sections 2 and 3 of operat­
ing instructions „PSI 6xxx: Weld timer with medium-frequency in­
verter“ (doc. no. 1070080028; also refer to page 5).
• Preceding safety instructions:
They refer to topic-related matters and are provided at the beginning
of a chapter or at the beginning of a whole procedure.
• Integrated safety instructions:
They are related exactly to a separate procedure step and are
provided right before the relevant step within the procedure.
A safety instruction is always structured as follows:
• Warning sign (only in case of personal injury)
• Signal word to indicate the danger level
• Type and source of danger
• Consequences of failure to observe
• Action for averting danger.
Table�2: Example for the structure of a safety instruction
Warning sign + SIGNAL WORD
Type and source of danger!
Consequences of failure to observe!
� Action for averting danger.
� Further action(s) for averting danger.
Integrated safety instructions may be embedded in the format of the
environment so that no ”visual” break in the action sequence is pro­
voked. Therefore they do not necessarily use the layout shown in the
example but they do use the indicated structure.
Where?
Structure?
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Regarding this documentation
The safety instructions are classified into danger levels (danger
classes). The signal word represents the danger level.
Table�3: Danger classes according to ANSI Z535.6-2006
Signal word Description
DANGER Dangerous situation where death or serious physical injuries
will occur if it is not avoided.
WARNING Dangerous situation where death or serious physical injuries
may occur if it is not avoided.
CAUTION Dangerous situation where light to moderate physical injur­
ies may occur if it is not avoided.
NOTICE Situation where damage to property or the environment may
occur if it is not avoided.
Table�4: Examples for classification of safety instructions
DANGER
Type and source of danger!
Consequences of failure to observe!
� Action for averting danger.
WARNING
Type and source of danger!
Consequences of failure to observe!
� Action for averting danger.
CAUTION
Type and source of danger!
Consequences of failure to observe!
� Action for averting danger.
NOTICE
Type and source of danger!
Consequences of failure to observe!
� Action for averting danger.
Danger levels?
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Regarding this documentation
1.3.2 Icons
The following icons are used to mark text passages specifically.
Table�5: Icons used
Icon Description
This icon indicates a tip or an information. It helps use
and operate the product optimally or understand the
context better.
� This icon indicates the need to observe/perform certain
things.
• This icon indicates an (unsorted) list.
1.
2.
3.
This icon indicates a (sorted) list or specific procedure
steps where a certain sequence has to be observed.
1.3.3 Designations
The following designations may appear in our documentation:
Table�6: Designations
Designation Description
BOS Welding user interface
PE Protective Earth. PE conductor.
PG Programming terminal/welding computer
PLC Programmable Logic Controller.
PSG Transformer-rectifier unit for PSI types.
Medium-frequency welding transformer 1000 Hz
PSI Programmable weld timer with inverter.
PSQ 6000
XQR
Plug-in module for PSI with UI controller functionality.
Is not needed for PSI 6xCx types.
PST Programmable weld timer with thyristor power unit.
Timer Weld timer. 
Also referred to as timer or resistance weld timer.
1.3.4 Abbreviations
Refer to Sect. 14 starting on page 111.
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Safety instructions
2 Safety instructions
� Please note the section with the identical name in the operating in­
structions „PSI 6xxx: Weld timer with medium-frequency inverter“
(for information on document number, refer to page 5).
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Safety instructions
Notes:
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General information on damage to property and products
3 General information on damage to property and
products
� Please note the section with the identical name in the operating in­
structions „PSI 6xxx: Weld timer with medium-frequency inverter“
(for information on document number, refer to page 5).
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General information on damage to property and products
Notes:
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Scope of delivery
4 Scope of delivery
� Please note the section with the identical name in the operating in­
structions „PSI 6xxx: Weld timer with medium-frequency inverter“
(for information on document number, refer to page 5).
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Scope of delivery
Notes:
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General information on the „ALR license option“
5 General information on the „ALR license option“
5.1 Functions and options
What does the „ALR license“ option do?
The option allows the process regulation and monitoring for aluminum
spot welding tasks.
In this context the process controller ensures that
• in the sequence modes ”Single spot” (robot) and ”Repeat” (manual
guns)
• during the 1st and 2nd current block
• the necessary amount of heat is supplied to an aluminum spot weld.
The basis of the „ALR license“ option is the „infrastructure“ of our „UI
regulation“ option, extended by the evaluation of the „Force“ process
variable and the use of new regulation algorithms.
By activating the option, the behavior of the process regulation can be
adapted specifically to the requirements of aluminum welding tasks. 
In this state, the system uses thefeedback of the „Force“ process vari­
able to supply the correct amount of heat to the spot weld.
By deactivating the option the behavior of the process regulation is
changed to „UI regulation“.
In this state, the system uses the feedback of the „Resistance“ process
variable (calculated from the measured value of current and voltage) to
supply the correct amount of heat to the spot weld. This type of process
regulation is suited optimally for steel welding tasks.
How to activate/deactivate the process regulation and monitoring for
aluminum spot welding is described in Section 5.4 from page 24.
How does this work?
1. Based on a faultless welding in KSR mode, the system determines
the curve of the process variable „Force“ as a function of time.
For basic information on the force characteristic during an aluminum
weld, please refer to Section 6 from page 25.
2. Ideally on the basis of several force characteristic curves obtained in
this manner, a mean curve (reference curve) is created for a spot
weld.
3. Based on this reference curve, the process controller is able to
change the amount of current and weld time of the 2nd current block
so that the learned amount of heat will be supplied to the aluminum
spot weld securely even if different interfering variables occur.
NOTICE
Simultaneous welds at the same component
Voltages and currents which are coupled into the measuring pro­
cess from outside may simulate a disturbed welding process. This
may lead to unnecessary controller interventions.
� Always avoid situations where several spots are welded within a
short distance on the same component simultaneously.
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General information on the „ALR license option“
NOTICE
Component movements during the welding process
Component movements caused e.g. by other active welding guns
or other forces acting on the workpiece may influence the force
measurements during the welding process.
This may lead to unnecessary controller interventions.
� Please always avoid situations during the welding process which
may adversely affect the force measurement.
What interfering variables can be compensated?
• Electrode wear
• Different sheet thicknesses / additional sheet
• Different coatings
• Force changes
• Mains voltage changes
• Shunt circuits
• Bad fit
Benefits / advantages of the option?
• Broad range of interfering variables can be compensated
• Considerably fewer user interventions necessary when interfering
variables occur
• Better and more precise monitoring of your aluminum welding pro­
cess by a large variety of monitored parameters (refer to Section 8
from page 59).
• Simple and rapid parametrization of the monitoring functions by
graphic representation of the actual value distribution over time (his­
togram display. Refer to page 66)
• Additional functions help improve and assure your welding quality
(e.g. gun resistance compensation, Q stop logic)
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General information on the „ALR license option“
5.2 Requirements
• Weld timers with TriCore-CPU (types PSI 6xCx).
• Licence Memory Card (Micro SD memory card) with the following op­
tions
• „UI controller“ license
• „Force monitoring“ license and
• „ALR“ license.
Having selected the relevant timer, you may - via BOS - display the
active licenses in the „Diagnosis“ topic under the „Fw options“ tab.
Information on the installation/removal of the Licence Memory Card
is provided in the operating instructions „PSI 6xxx: Weld timer with
medium-frequency inverter“ (doc. no. 1070080028; also refer to
page 5).
• Primary or secondary current measurement with functioning sensor
technology.
• Correctly wired voltage tapping at the gun arms (refer to Section
5.3.1 from page 20).
• Alternatively:
• a force sensor with analog feedback signal mounted and wired on
the gun arm correctly, or
• an electrode gun control which is able to transmit the force actual
value with sufficient accuracy and speed to the weld timer as ana­
log or digital signal.
• Use of the BOS user interface for parametrization and visualization.
Information on the BOS 6000 user interface is provided in the „BOS
6000 online help“ (doc. no.�1070086446; also refer to page 5).
5.3 Information on assembly and connection
When a new weld timer is delivered, the matching timer firmware and
the necessary License Memory Card has already been integrated.
Please note in this case:
1. If you wish to use secondary current measurement, a matching cur­
rent sensor has to be installed in the secondary circuit and wired cor­
rectly.
2. Make sure that the appropriate feedback of the „Force“ process vari­
able is ensured.
• In case of analog feedback:
For connection of a feedback signal, a timer type with force feed­
back option on X9 (terminals 4 and 5) is necessary.
Information on this topic is provided in the operating instructions
„PSI 6xxx: Weld timer with medium-frequency inverter“ (no.
1070080028) in Section „Electrode force feedback“.
• In case of digital feedback:
To use a digital feedback signal, a timer type with matching inputs
in the I/O field or integrated servogun function is necessary.
Information on whether your unit supports the respective feedback
option is provided in the type-specific supplement of the operating
instructions.
When a new weld timer is de­
livered
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General information on the „ALR license option“
3. Switch on the 24 VDC logic supply of the weld timer.
The weld timer now has to start up without any errors.
4. Check via BOS in the „Diagnosis“ topic under the „Fw options“ tab
whether the following licenses are displayed after selecting the rel­
evant timer:
• UI controller license,
• Force monitoring license and
• ALR license.
If that is the case, all required options were recognized by the timer
firmware.
If that is not the case, please write down the software edition of your
• BOS (BOS 6000 title bar)
and contact our Service.
5. Use the BOS to set the „Current measurement“ parameter correctly
under the „Programming“ topic, „General“ tab.
6. Parametrize the force feedback in accordance with the feedback op­
tion used. 
For information on parametrization, refer to Section 5.3.2 from
page 22.
Proceed as follows to retrofit a weld timer:
1. Switch off the 24 VDC logic supply of the weld timer.
2. Remove the operating unit of the diagnosis module.
3. Slide the License Memory Card with the activated option into the
Micro SD slot.
Information on the installation/removal of the Licence Memory Card
is provided in the operating instructions „PSI 6xxx: Weld timer with
medium-frequency inverter“ (doc. no. 1070080028; also refer to
page 5).
4. Plug the operating unit of the diagnosis module on again.
5. If you wish to use secondary current measurement, a matching cur­
rent sensor has to be installed in the secondary circuit and wired cor­
rectly.
6. Make sure that the appropriate feedback of the „Force“ process vari­
able is ensured.
• In case of analog feedback:
For connection of a feedback signal, a timer type with force feed­
back option on X9 (terminals 4 and 5) is necessary.
Information on this topic is provided in the operating instructions
„PSI 6xxx: Weld timer with medium-frequency inverter “ (no.
1070080028) in Section „Electrode force feedback“.
• In case of digital feedback:
To use adigital feedback signal, a timer type with matching inputs
in the I/O field or integrated servogun function is necessary.
Information on whether your unit supports the respective feedback
option is provided in the type-specific supplement of the operatinginstructions.
7. Switch on the 24 VDC logic supply of the weld timer.
The weld timer now has to start up without any errors.
When the WT is retrofitted
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General information on the „ALR license option“
8. Check via BOS in the „Diagnosis“ topic under the „Fw options“ tab
whether the following licenses are displayed after selecting the rel­
evant timer:
• UI controller license,
• Force monitoring license and
• ALR license.
If that is the case, all required options were recognized by the timer
firmware.
If that is not the case, please write down the software edition of your
• BOS (BOS 6000 title bar)
• Weld timer (via BOS in the „Diagnosis“ topic under the „Timer in­
formation“ tab)
and contact our Service.
9. Use the BOS to set the „Current measurement“ parameter correctly
under the „Programming“ topic, „General“ tab.
10.Parametrize the force feedback in accordance with the feedback op­
tion used. 
For information on parametrization, refer to Section 5.3.2 from
page 22.
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General information on the „ALR license option“
5.3.1 Voltage tapping
The voltage signal measured is influenced by the properties of the
transformer, the temperature rise in the secondary cables and flexible
links and their wear due to movement. 
Since these interfering variables hardly exist on the gun arms, it is re­
commendable to connect the voltage measuring cables there.
The closer the voltage tap is positioned to the electrodes/shafts, the
smaller the influence of the gun resistance on control and monitoring
processes.
In this context, using the „Gun resistance compensation“ functional­
ity is also useful (see from page 91).
Basic information concerning compliant designs is provided in
standard EN 60204-1: (Safety of machinery - electrical equipment of
machines - part 1: „General requirements“ - Section 13.4.3: Connec­
tion to moving elements of the machine).
Shielded cable (max. 100 m)
Welding transformer
Highly flexible cable
(max. 1m)
Fig.�1: Voltage tapping
� Install the voltage tapping behind the secondary cable or flexible
links (looking towards the electrodes).
� Connect voltage measuring cables on the gun arm permanently and
with low impedance by clamping a suitable cable lug under an exist­
ing screwed connection.
� Where the voltage measuring cables are moved by the gun, use
highly flexible cable with 0.5 to 1.5 mm2 cross-section. As only one
core is connected to each gun arm, the cable may be unshielded in
this area over a length of approx. 1 m. 
From there, and before the voltage cable is routed together with
other cables, shielded cables must be used for further routing.
� The shield of the voltage measuring cable must be routed to the weld
timer - also through further plugged connections - and must be ex­
clusively connected at the entry to the control cabinet/Schweisskof­
fer or on the weld timer side, respectively, to frame potential using a
thoroughly conductive, large area connection.
� A plugged or clamped connection is useful at the connection point
between unshielded and shielded cables for easy replacement of
voltage measuring cables.
� Always install the voltage measuring cables so as to ensure that the
movement of the gun is not obstructed and the cables are not dam­
aged.
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General information on the „ALR license option“
� The cable's permitted bending radius must be observed in the mov­
ing points.
� Please ensure sufficient strain relief and fastening of the cable.
Connection of the voltage measuring cables to the weld timer (WT):
via X3.
Information on this terminal assignment is provided in the operating
instructions „PSI 6xxx: Weld timer with medium-frequency inverter“
(doc. no. 1070080028; also refer to page 5) in Section „Measuring
input for secondary voltage“.
Suitable cables and ring terminals
• For use in the area of the gun or gun arm:
• Unshielded cable, e.g. single leads of the type „Ölflon FEP“
Messrs. Lapp
• Solistrand ring terminals made from electrolytically tin-plated cop­
per (e.�g. type 34124 Messrs. Tyco Amp)
• For use in the remaining area:
• shielded cable, 2 x 0.75 mm2, twisted pair
(corresponding to part no. 1070 913 494:
consisting of 2 x 2 x 0.75 mm2, LiYCY; 2 pairs of cores for elec­
trode voltage and current sensor signal)
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General information on the „ALR license option“
5.3.2 Parameterization of the force feedback
1. Adjust the parameters in the „Programming“ topic, „PSQ“ tab,
„Force“ subtab to the application used.
The tab is only displayed when the „Force monitoring“ option (Li­
cense Memory Card) is activated.
Fig.�2: „Programming“ topic, „PSQ“ tab, „Force“ subtab
„Interface force input“ parameter:
None:
No force feedback.
� The setting „None“ must not be used when the „Process regulation
and monitoring“ option for aluminum spot welding is used because
the process controller needs the „Force“ variable.
Analog on:
Use of an external force sensor. The force actual value is signaled to
the timer via X9 (terminals 4 and 5) as analog signal (0 - 10 VDC).
Servo gun:
The force actual value is signaled to the timer digitally.
„Polarity input signal“ parameter:
NEG_POL / POS_POL:
Allows a change of the input signal polarity without rewiring.
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General information on the „ALR license option“
„Force calibration value“ parameter:
Defines how the timer should convert the actual analog voltage into
force. 
Example: Input value „1.5“ -> 1V is equivalent to a force of 1.5 kN
„Force offset“ parameter:
Allows compensation of a constant offset voltage at the analog input.
Example: Input value „200“ -> force actual value = measured value +
200�N
„Selection reset signal“ parameter:
In order to inform a connected force sensor when force measure­
ment should be active, the timer uses the OR function to link
• the status of an enable signal for force measurement generated
internally (set with program start and reset after HLD)
• with the status of the digital „Operate force sensor“ input (external
enable for force measurement).
The result of linking both signals is reported at the „Operate signal“
timer output signal (X9 terminal 1; 0 V or 10� V).
Using the „Selection reset signal“ parameter, the logic of the „Oper­
ate signal“ output signal may be adjusted to the requirements of the
used force sensor:
Off:
The „Operate signal“ output signal is not used.
Pos:
10 �V at the „Operate signal“ output signal shows that force measure­
ment should be active.
Neg:
0 �V at the „Operate signal“ output signal shows that force measure­
ment should be active.
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General information on the „ALR license option“
5.4 Activating/deactivating the option
1. Adjust the „Mode version“ parameter in the „Programming“ topic,
„PSQ“ tab, „UIR“ subtab to the application used.
Roboter_Alu
Fig.�3: „Programming“ topic, „PSQ“ tab, „UIR“ subtab
„Mode version“ parameter:
Aluminum:
Timer-global activation of the process regulation and monitoring for
aluminum spot welding. 
The behavior of the process regulation is adapted to the require­
ments of aluminum welding tasks.
Steel:
Timer-global deactivation of the process regulation and monitoring
for aluminum spot welding. 
The behavior of the process regulation is changed to „UI regulation“
For information on how to activate/deactivate the selectedprocess
regulation for one welding program, refer to Section 7.4 from page
48.
Detailed information on „UI regulation and monitoring“ is provided in
a separate document (for document number, refer to the table on
page 5).
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Basics
6 Basics
Aluminum spot welding tasks are in part considerably different from
steel welding tasks:
Table�7: Basic differences between steel and aluminum welding tasks
Property
Pure iron
(FE)
Aluminum
materials
EN-AW ...,
AA ...
Effects on 
aluminum spot welding tasks
Possible / necessary reactions
Spec. electric
conductivity 
[m / (Ω mm2)]
10.3 17 ... 36 • Lower material resistance
• Lower heat transformation
• Greater influence of shunts
• Increase welding currents
(up to approx. 50 kA, if ne­
cessary)
• Position the spots optim­
ally and accurately
• Take into account clamp­
ing positions relative to the
required spot positions
Spec. thermal
conductivity
[W / mK]
67 120 ... 235 • Great influence of cooling
• Stronger influence of work­
piece geometry and spot
position
• Increase welding currents
(up to approx. 50 kA, if ne­
cessary)
• Create good and constant
cooling conditions
• Position the spots optim­
ally and accurately
Melting temper­
ature
[�C]
1532 658 • High dynamics in the melt­
ing behavior
• Decrease weld times
(typ. 70 ... 120 ms)
• Use guns with fast reposi­
tioning behavior
Surface quality good con­
ductivity, tar­
geted use of
coating
low con­
ductivity,
oxidation
• High contact resistance at
the beginning of the weld
• Quick alloying of the work­
piece to the electrodes.
• Stronger tendency to elec­
trode sticking
• High electrode wear
• Use slope for better coup­
ling
• Considerably reduce
dressing intervals
• Wash sheets
• Use special coats of the
sheets
That is why a process regulation and monitoring procedure is required
which is specifically optimized for aluminum.
The process controller uses a large variety of information from the weld­
ing process to perform its regulation task. At various times during the
welding process, it scans different measured quantities to calculate the
„current“ and „weld time“ influencing variables.
It thus considers the secondary circuit resistance in addition to the gun
force as well as information concerning expulsion and the temporal re­
lationship of the individual quantities.
For a better understanding of the process of a welding task, it is there­
fore important to know more about the force characteristics.
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Basics
6.1 Interpretation of the force characteristics
Due to the thermal expansion during the weld time, the material is
„pressed“ against the electrodes. This leads to an increase of the actual
force measured. 
From the characteristic of the actual force, it is possible to draw conclu­
sions about the thermal and mechanical processes taking place during
the welding process and derive an assessment of the welding quality.
F [kN] or I [kA]
tSQZ WLD HLD
CurrentForce
Fig.�4: Impact of thermal expansion on the actual force
These characteristics can be visualized using the �BOS user inter­
face, e.g. under the „Diagnosis“ topic, „PSQ“ tab. Detailed informa­
tion on all available display functions are provided via the BOS online
help.
When the process controller is active, this visualization can be used
to detect controller interventions and changes in the process situ­
ation.
In constant-current regulation mode (KSR), this visualization may be
used to monitor process changes after a variation of the welding
parameters and use these findings for further optimization.
The figures below show several force characteristics of welds without
faults.
All characteristics are based on the same sheet combination where the
current was increased in 500�A steps from 4 to 11 kA and the other
parameters have remained identical:
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Basics
Force [N]
Time [ms]
1
2
3
4
5
7
8
6
9
10
11
12
13
15
14
1
2
3
4
5
7
8
6
9
10
1112
13
15
14
13
Fig.�5: Examples of force curve characteristics
All force characteristics were recorded under ideal conditions. Most
characteristics obtained under production conditions are much more
difficult to interpret as a consequence of process disturbances or
electrode gun properties.
• In case of low currents, the material between the electrodes is not
heated sufficiently and therefore expands only little.
This results in very flat curve characteristics (refer to curves 1 to 5;
current range 4 to 6 kA).
• As current increases, material heating generates a growing counter­
force against the electrodes.
This leads to increasingly steep slopes at the beginning of the force
characteristic.
• At 9.5 and 10 kA (curves 12 and 13), the resulting force characteristic
first shows a steep slope, then the force characteristic drops again
slowly. This drop is caused by the electrodes sinking in. The best
weld was obtained at 9.5 kA.
• Curves 14 and 15 (at 10.5 and 11 kA) drop abruptly after a very steep
slope. These are expulsion welds.
6.2 Interpretation of the resistance curves
The resistance of the aluminium compound drops from relatively high
values at the beginning of the weld because the sheets warm up and
the breaking of the oxide coats to a low value.
This phase is referred to as the "contact phase".
Since the material resistances are very small, it can be seen no signific­
ant change in the resistance curves of welding. The resistance value
drops continuously until the end of the weld time. During this phase, the
spot to be welded grows to the spot diameter to be reached.
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Basics
6.3 Welds with insulating materials
Especially when using adhesives, insulating layers are encountered
between the sheets to be welded. When used properly, these materials
do not present an obstruction to the weld. However, their insulating ef­
fect first has to be overcome before welding can start.
At the beginning of the weld time, resistance remains high until the insu­
lating layer is driven out or has been burnt off. The duration of this phase
depends on the material used and the electrode gun force, among oth­
ers.
When the insulation has been removed, the weld will be executed as
normal, and the force characteristics will be determined by the sheet
combination.
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Basics
6.4 Welds with expulsion
Expulsion can be detected by a sudden change towards lower force
values in the force characteristic.
When the system should interpret this kind of change as expulsion
can be parametrized in the „Programming“ topic, „PSQ“ tab, „UIR“
subtab via the „Detection of expulsions“ and „Expulsion decay time“
parameters.
A detected expulsion is indicated by the system via expulsion signal
incl. the expulsion point in time if the voltage and force measurement
was activated for the respective weld:
Although the process controller compensates many interferences, ex­
pulsions can nevertheless occur during active process regulation. The
cause may be the occurrence of a single very strong interference as
well as the interaction of several interference variables.
The controller's response to expulsions can be set with regard to cur­
rent in the „Programming“ topic, „PSQ“ tab, „UIR“ subtab via the „Ex­
pulsion current control“ parameter. 
With regard to time an active process regulation automatically ex­
tends the weldtime to a certain extent in order to make up for the
energy lost in the material.
The active process controller furthermore offers the possibility of
varying the energy input through %I correction. A spot-weld-related
lowering of the heat may thus also be used for the temporary
„manual“ elimination of expulsion.
For the optimization of welds with expulsion, it is helpful to know the time
the expulsion occurred. Several options to avoid expulsion can be de­
rived:
� Avoid edge welds. Spot position has to be optimized, if necessary.
� In case of unresolvable fitting problems, use an upslope or a longer
slope, respectively. This improves coupling.
� Check whether the programmed ratio of current to force is correct.
� If force is within the correct range, reduce the current.
� Check whether the repositioning behavior of the welding system is
ok.
� If the expulsion occurs just before the end of the weld time, reduce
the weld time slightly.
Expulsion symbol
with expulsion point in time
Expulsion
in the 1st and 2nd third of the
weld time
Expulsion
in the last third
of the weld time
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Basics
Notes:
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Commissioning of the process control
7 Commissioning of the process control
7.1 Basic requirements
• A properly completed basic commissioning of the system. 
Information on this topic is provided in the operating instructions
„PSI 6xxx: Weld timer with medium-frequency inverter“ (no.
1070080028) under Section „Commissioning“.
• Taking into account the information provided in Section 5.2 to 5.4
(refer to page 17 et seq.).
• Appropriately set transformer, current and force calibration paramet­
ers.
• Perfect condition of gun and electrode shafts.
• Correct cooling conditions at the gun (water tubes, cooling water
quantity, supply temperature).
• The gun forces generated are in accordance with the command value
inputs and are reproducible.
• Correctly positioned, flat type A electrode tips which match the weld­
ing task (refer to DIN ISO 5821).
• The electrode tips are not excessively worn. 
Recommendation: max. tip wear: 30 welds.
Oxide deposits on the tips have been removed.
• Welding equipment and parts to be joined must be suitable for the
welding task (forces, positioning, cooling, flange width, etc.).
• Interferences are eliminated or at least reduced to a minimum.
• Matching (KSR) basic parametrization of the respective weld. For
more information on this topic, refer to Section 7.2.
How to generate reference curves is described in Section 7.3 from
page 36.
7.2 Determining the basic welding parameters
We recommend to use a separate program for each combination of
different sheet thicknesses and to determine separate reference
curves.
Advantage: when using separate programs, all welding parameters
can be optimally set for the welding task in question and later in the
process control mode, the weld time will not become longer than ne­
cessary based on the different sheet thicknesses.
The basic welding parameters of a spot weld to be configured can be ob­
tained from various sources:
• Accepting the welding parameters from a system with the same weld­
ing task that operates reliably
• Results of lab examinations
• DVS tables
• Manufacturer-specific, internal standard
• Calculation programs
• Database of welding parameters
• Simulation programs
... especially at the weld timer
... especially at the gun
... generally at the plant
... and additionally for genera­
tion of a reference curve
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Commissioning of the process control
The approach chosen in this context is dependent on the existing cir­
cumstances, options and the time frame available.
How basic parameters are determined may have considerable influ­
ence on the later process stability and the scope of possibly required fol­
low-up optimization.
We distinguish between 3 variations in this context:
1. Determination using original component at the production plant.
+ Optimally suited for subsequent generation of reference curves.
+ Special features typical of component/production have little im­
pact on subsequent process control/monitoring (shunt circuit, ro­
bot positioning). This reduces optimization requirements, if any,
after conversion to process control.
+ Very good basis for the monitored parameters process stability
(PSF), process quality (UIP) and force quality factor (FQF).
+ Influence of dress cycles is taken into account.
This is important should it be necessary later to switch off the pro­
cess control mode (return to KSR mode) temporarily.
+ Suitable if sufficient components for determination of the basic
parameters are available.
- High costs due to scrap rate during tests (components).
- Production on the relevant lines is not possible or only with restric­
tions during determination of the basic parameters.
2. Determination using sheet strips on the production plant.
+ Low costs due to scrap during tests.
+ Well-suited if no/few components are available for determining the
basic parameters (e.�g. for new sheet thickness/material combina­
tions).
+ Suitable for subsequent generation of reference curves.
- Special features typical of component/production may have a
great impact on subsequent process control/monitoring (shunt cir­
cuit, robot positioning, wear). This increases optimization require­
ments, if any, after conversion to process control mode.
- The basis for the monitored parameters process stability (PSF),
process quality (UIP) and force quality factor (FQF) is not as good
compared to the option 1.
- Production on the relevant lines is not possible or only with restric­
tions during determination of the basic parameters.
3. Determination using sheet strips in the lab
+ The ongoing production on the relevant lines is not influenced dur­
ing determination of the basic parameters.
+ Low costs due to scrap during tests.
+ Well-suited if no/few components are available for determining the
basic parameters (e.�g. for new sheet thickness/material combina­
tions).
+ Suitable for subsequent generation of reference curves.
- Not suitable for the subsequent generation of the reference curves
- Reference curves must be determined at the production plant.
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Commissioning of the process control
- Subsequent process control / monitoring may be strongly influ­
enced by component-/production-typical features (shunt, robot
positioning, wear, gun properties) under certain circumstances.
The objective is, in any case, the optimal (KSR) basic parametrization of
the respective weld.
Procedure
1. Make sure that neither the program-related nor the electrode-related
I% and pressure correction for the spot weld is active.
2. Make sure that a possibly necessary I% stepping for compensation of
the effects of electrode wear is parametrized correctly.
3. Make sure that KSR mode is active for the respective weld.
4. Make sure that automatic reweld is switched off for the respective
weld.
5. Make sure that the voltage measurement is active for the respective
weld ("Programming" topic, "PSQ" tab, "UIR" subtab: "Measurement
(S)" and "Measurement (P)" parameters are „ON“).
6. Make sure that regulation and monitoring have been deactivated for
the respective weld („Programming“ topic, „PSQ“ tab, „UIR“ subtab:
„Regulation (P)“ and „Monitoring (P)“ parameters are „Off“; refer to
page 57).
7. Determine the required SQZ squeeze time.
It must be chosen so that the programmed force has been completely
builtup and is constant when the weld time starts.
The squeeze time should be individually verified and adjusted (if ne­
cessary) for each type of gun.
For manual guns, a squeeze time of at least 1000 ms is generally ap­
propriate.
In the figure below, it is clearly shown that the programmed force of
3.2 kN is only built up after about 300 ms:
Force (in N)
Time (in ms)
Fig.�6: Example: Force build-up during the squeeze time
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Commissioning of the process control
 
8. Determine the HLD hold time.
The length of the HLD may depend on the sheet combination. 
Tests have shown that a hold time of 100-200 ms is generally appro­
priate.
9. Determine weld time, amount of current and force.
Possible initial parametrization as starting point for the optimization of
aluminum spot welds for sheet thicknesses of 1 to 1.5 mm:
Tip type: A
PreWLD: 400 ms; 8 kA
MainWLD: 160 ms; 25 kA
Slope: 70 ms; from 8 to 25 kA
Force: approx. 6 kN
Tip dress cycles: every 20 to 30 spot welds
Tip dress force: approx. 1 kN
• Notes:
• An upslope is recommended especially in the event of ad­
hesive, fitting problems and thick sheet stacks.
• Notes on force:
• If several sheet thickness and material combinations have to be
covered by a single welding program (e.�g. for manual guns),
the force should be defined with due regard to the sheet
strength towards the thicker sheet combinations.
10.Always take into account the special features of the relevant welding
task.
If several sheet thickness and material combinations have to be
covered by a single welding program (e.�g. for manual guns), take into
account the thinnest sheet.
11.Perform a test weld with the parameters set and visualize their force
characteristic.
Information on the force characteristic and its visualization is
provided in Section 6 from page 25.
12.Verify the required quality of the welding result by means of destruct­
ive test and ultrasonic measurement, if necessary.
The objective is, in any case, an optimal (KSR) basic parametrization
of the respective weld with the following main properties:
• The welding result ranges above the minimum requirements.
• The resulting spot diameter is slightly larger than the nominal dia­
meter.
• Dynamic force characteristic with the greatest possible force
changes at the beginning. Curves of this kind can be observed well
and indicate a stable process situation.
Information on the force characteristic and its visualization is
provided in Section 6 from page 25.
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Commissioning of the process control
Welding quality cannot be assessed by interpreting the curve
characteristic but only by means of the spot diameter and possibly
by ultrasonic measurements! Controlling the curve characteristics
must be limited to assessment of the force characteristic: 
It should increase strongly at the beginning (thermal expansion in­
creases force proportionally to the current) and then only increase
„moderately“ to a maximum.
• Expulsion-free schedule.
Also refer to Section 6.4 from page 29.
In many cases, a sticking of the tips - caused by surface coatings of
the aluminum (oxidation inhibitors) - can be observed.
A well-tried countermeasure in these cases is washing the sheets or
using dry lubricants.
13.If the current parameter configuration generates an optimal and
stable weld, generation of the related reference curve (refer to Sec­
tion 7.3 from page 36) is permitted.
Otherwise, optimize the parameters and move to step 11.
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Commissioning of the process control
7.3 Generating reference curves
To generate a reference curve, it is necessary to record the force char­
acteristic during one or several faultless welds.
The following options are available for this purpose:
• Defining the force curve as reference curve. 
Manual selection of a program-specific force characteristic which is
then loaded into the controller as program-specific reference curve.
For procedure, refer to Section 7.3.2 from page 37.
• Recording by recorder.
Automatic recording of force characteristics with subsequent filtering
and mean value definition. The resulting program-specific mean
value curves can then be loaded into the controller as program-spe­
cific reference curves.
For procedure, refer to Section 7.3.3 from page 40.
7.3.1 Requirements
� If you wish to use the „Gun resistance compensation“ functionality,
the function has to be activated. 
For information on activation, refer to Section 11.1 from page 92.
� Make sure that the optimal (KSR) basic parameters have already
been defined and programmed for the respective welds (refer to Sec­
tion 7.2 from page 31).
%I compensation should be set to 0%, if possible, in order to be able
to use all compensation features later in process control mode.
� Make sure that the electrode tips are not too strongly worn (max tip
wear: approx. 30 welds) and are free from oxide.
� Make sure that the voltage measurement is active for the respective
welds („Programming“ topic, „PSQ“ tab, „UIR“ subtab: „Measure­
ment (S)“ and „Measurement (P)“ parameters).
� Make sure that the force measurement is active for the respective
welds („Programming“ topic, „PSQ“ tab, „Force“ subtab: parameter
Interface force input.
� Make sure that process regulation and monitoring have been deactiv­
ated for the respective weld („Programming“ topic, „PSQ“ tab, „UIR“
subtab: „Regulation (P)“ and „Monitoring (P)“ parameters are „Off“;
refer to page 57).
� If the force characteristics are not generated on a component but a
sheet strip, the following applies:
• Do not use the force characteristic of the first spot on a sheet to
define or determine a reference curve.
• Leave a clearance of at least approx. 45 mm between the spot
welds.
� Do not use welds with expulsion to define a reference curve.
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Commissioning of the process control
7.3.2 Defining the force curve as reference curve
1. Observe the requirements referred to in Section 7.3.1 on page 36.
2. Choose which BOS window is best suited to define the reference
curve for your project.
• „Programming“ topic, „PSQ“ tab, „UIR reference“ subtab
Basic options:
• After selection of spot name (1a) or weld timer and program
number (1b), the corresponding last measured force character­
istic can be loaded into the display (2), saved as *.rui file (3), or
defined as new reference curve of the respective program (4).
• A saved force characteristic can be loaded into the display (5),
saved under a different name as *.rui file (3), or defined as new
reference curve (4) of the currently selected program (1b).
[1a]
1b
2
3
4
5
Fig.�7: Window „Programming“,“PSQ“ tab, „UIR Reference“ subtab
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Commissioning of the process control
• „Diagnosis“ topic, „PSQ“ tab
Basic options:
• After selection of the relevant weld timer (1) and stopping the
window update (3), the last 64 measured force characteristics
are loaded into the display via scroll bar (2) and defined as new
reference curve of the corresponding program (7).
• A currently shown force characteristic can be examined on the
basis of the following functions:
• Display of the data (6) at the current position (4a, 4b) of the
selected cursor (4)
• Display of min., max. or mean value (5) between the two
cursor lines (4a, 4b).
1
3
2
7
4a
6
5
4
4b
Fig.�8: Window „Diagnosis“,“PSQ“ tab
3. If you use the BOS window in the „Diagnosis“ topic,„PSQ“ tab, (see
above), choose the „Program“ option in the „Filter“ area (3) and indic­
ate the program to be used for recording the data in the further
course.
4. Perform the test weld(s).
5. Check the weld quality by means of the spot diameter and ultrasonic
measurements, if necessary. In the further course, you should only
use force characteristics of faultless welds.
6. Load the corresponding force characteristic into the display and
define it as new reference curve.
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Commissioning of the process control
Process control mode can then be activated for the respective weld. For
information on this topic, refer to Section 7.4 from page 48.
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Commissioning of the process control
7.3.3 Recording by recorder
1. Observe the requirements referred to in Section 7.3.1 on page 36.
2. Choose the „Settings“ topic, „UIR setup“ tab, „Recording mode“ com­
mand button (1).
The „UI setup“ application (2) is started.
After starting the „UI setup“ application, the command button text (1)
changes from „Recording mode“ to „Exit BOS_UI_Setup“.
The „UI setup“ application can only be closed again using this com­
mand button.
1
2
3 4 5 6 7
9
8
Fig.�9: “UI setup” window: Recording by recorder
3. Use the left checkbox (Fig. 9: Position 3) to determine the weld timers
for which the recorder function is to be activated.
4. Use the checkbox in the „New recording“ columns (Fig. 9: Position 7)
to determine whether available recorded force characteristics (Fig. 9:
Position 4) are to be deleted before the recording of further curves is
started.
In the status area for recording (Fig. 9: position 8), the system shows
you the current program-related number of all available recordings
for the weld timer selected on the left (blue line).
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Commissioning of the process control
5. If needed, limit the recording to
- selectable programs (Fig. 9: Position 5)
- Programs without active process control (Fig. 9: Position 6).
6. Start recording using the „Start recording“ command button (Fig. 9:
Position 9).
In the status area for recording (Fig. 9: Position 8), you can observe
the recording progress.
After the start of recording, the command button text (Fig. 9: Posi­
tion 9) changes from „Start recording“ to „Stop recording“.
7. When the scope of recording meets your requirements, stop the cur­
rent recording using the „Stop recording“ command button (Fig. 9:
Position 9).
8. Close the „UI setup“ application.
To do this, bring the BOS window to the foreground again and select
the „Exit BOS_UI_Setup“ command button in the „Settings“ topic,
„UIR setup“ tab.
The „UI setup“ application is exited.
The system then shows you the curves recorded for a program as
“pencil of curves” (see Fig. 10:).
9. Check the weld quality by means of the spot diameter and ultrasonic
measurements, if necessary. In the further course, you should only
use force characteristics of faultless welds.
10.Delete all curves which are not suitable to create the reference curve
and then define the mean value curve (reference curve).
� Delete the welds with expulsion. For detailed information on welds
with expulsion, refer to Section 6.4 from page 29.
� If necessary, delete curves recorded immediately after dressing.
� Delete curves of welds, if needed, where (too high) %I correction
was active. Please note that %I correction can be caused by active
%I stepping (stepper; only relevant for KSR mode) as well as by
parameter setting in the „Corrections“ topic, „Correction“ tab.
%I stepping and wear of selected (Fig. 10: Position 1) actual
curves are displayed by the system (Fig. 10: Position 5).
This work can be performed both manually and automatically:
• Manually:
Select the relevant program and the actual curve to be deleted
(blue) (Fig. 10: Position 1) and activate the „Delete this curve“
command button (Fig. 10: Position 2).
Having deleted all the curves not needed, use the remaining
curves to create the mean value curve (Fig. 10: Position 3). The
mean value curve is displayed in red color. The black curves show
the minimal and maximal force characteristics. The result is shown
in Fig. 11:
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Commissioning of the process control
1
2
3
5
4
6
Fig.�10: Deleting superfluous force characteristics
Fig.�11: Display of the mean value curve (reference curve)
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Commissioning of the process control
• Automatically:
Press the „Delete + avg. curves“ command button (Fig. 10: Posi­
tion 4). The „Delete + avg. curves “ window appears:
1 2
3
4
Fig.�12: „Delete and average curves“ window
Use the left checkboxes (Fig. 12: Position 1) to determine the weld
timers for which the automatic procedure is to be activated.
Limit the automatic procedure to selectable programs (Fig. 12: Po­
sition 2) and/or certain criteria (Fig. 12: Position 3).
Effect of activated checkboxes:
• „Expulsion“:
Deleting welds with detected expulsion.
• „Current correction factor“:
Deleting welds with %I corrections greater than the specified
limit value.
• „Count“:
Deleting welds with electrode wear exceeding the specified lim­
its.
• „Create avg. curve“:
Define the corresponding program-specific mean value curves
(reference curves) from the remaining curves.
Click on the „Continue“ command button to start the automatic
procedure. 
If „Create avg. curve“ is active, the reference curves generated are
saved in the standard path for UI setup (can be set using the con­
figuration tool) under the „Reference_Curves“ directory sorted as
*.rui files according to weld timer designations.
The system saves information on deleted curves and generated
mean value curves in a log file which you can view using the „Detail
info“ command button (Fig. 12: Position 4).
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Commissioning of the process control
11.Transfer the mean value curve (reference curve) to the weld timer.
This action can also be performed manually or automatically.
NOTICE
Transfer of an unsuitable force characteristic
If an unsuitable force characteristic is declared as reference curve,
this may lead to frequent/major controller interventions or even to
unsatisfactory welding results.
� Make sure before you start the transfer that a suitable curve has
been selected. A selected curve is displayed in red color.
� Never trigger the transfer without reason.
• Manually:
Select the relevant program (Fig. 13: Position 1) or the relevant
program and the required (blue) actual curve (Fig. 10: Position 1)
and press the „Reference sequence --> Timer“ (Fig. 13: Posi­
tion 2) command button.
1
2
3
Fig.�13: Transferring the mean value curve to the weld timer
� Please note the subsequent completion message.
The transferred curve can only be used as reference curve if de­
clared as „valid“ by the weld timer:
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Commissioning of the process control
Fig.�14: Message reference curve is valid
When the transferred curve has been declared as valid, you may
activate the process control for this weld. 
How to activate process control is described in Section 7.4 from
page 48.
Programs with valid reference curves are easily recognized in the
„Overview“ topic using the „Curve valid“ option button. Refer to Sec­
tion 9.1.1 from page 76.
• Automatically:
Press the „Ref.curves (PC) -> SST“ command button (SST =
Timer) (Fig. 13: Position 3 or Fig. 10: Position 6). The „Ref. curves
(PC) -> SST“ window appears:
1 2
3 4 5 6
Fig.�15: „Ref. curves (PC) -> SST“ window (SST = Timer)
Use the left checkboxes (Fig. 15: Position 1) to determine the weld
timers for which the automatic procedure is to be activated.
Limit the automatic procedure to selectable programs (Fig. 15: Po­
sition 2), if necessary.
Press the „Ref. curves (PC) -> SST“ (SST = Timer) command but­
ton (Fig. 15: Position 5) to make a variety of settings for writing of
the curves („Settings for writing curves“ window is opened auto­
matically) and then start the automatic procedure.
If you want to open the „Settings for writing curves“ window only,
press the „Settings“ command button (Fig. 15: Position 3).
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Commissioning of the process control
1
2
3
Fig.�16: „Settings for writing curves“ window
Effect of activated checkboxes (Fig. 16: Area 1):
• „Special programs (excl.)“:
Transfer of mean value curves (reference curves) of certain
programs can be prevented here.
This is useful e.�g. for dressing and calibration programs.
• „Regulation on“:
If activated, the system switches on the program-specific pro­
cess control („Programming“ topic, „PSQ“ tab, „UIR“ subtab,
„Regulation (P)“ parameter) after transfer of a valid reference
curve.
• „Monitoring on“:
If activated, the system switches on the program-specific pro­
cess monitoring („Programming“ topic, „PSQ“ tab, „UIR“
subtab, „Monitoring (P)“ parameter) after transfer of a valid ref­
erence curve.
• „Reference values for UIR monitoring“:
If activated, the system determines reference values for the
program-specific process monitoring from the mean value
curve (reference curve) generated and also writes the values
into the weld timer after transfer of a valid reference curve. 
The values are provided under the „Programming“ topic, „PSQ“
tab, „UIR monitoring“ subtab in the „Reference“ input fields.
• „Reference value UIP=100“:
If activated, the system writes the reference value „100“ for the
„UIR“ monitoring variable into the weld timer in case of pro­
grams where the reference curve is generated on the basis of
mean value calculation.
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Commissioning of the process control
• „Tolerances“:
If activated, the system displays additional input options
(Fig. 16: Area 2) for definition of tolerances and to switch the
respective monitoring variables on/off (Fig. 16: Position 3). 
The settings made here are written into the weld timer as pro­
gram-specific monitoring data after transfer of a valid reference
curve. 
The values are provided under the „Programming“ topic, „PSQ“
tab, „UIR monitoring“ subtab in the corresponding input fields.
For detailed information on process monitoring, please refer to
Section 8 from page 59.
� Please note the completion message after transfer.
Transferred curves can only be used as reference curves if they
have been declared as „valid“ by the weld timer.
Whether that was the case is saved in a log file which you can view
using the „Detail info“ command button (Fig. 15: Position 4).
When a transferred curve has been declared as valid, process
control is possible for the respective weld and already activated
automatically depending on the „Regulation on“ checkbox
(Fig. 16: Area 1). 
How to activate process control manually is described in Sec­
tion 7.4 from page 48.
Programs with valid reference curves are easily recognized in the
„Overview“ topic using the „Curve valid“ option button. Refer to Sec­
tion 9.1.1 from page 76.
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Commissioning of the process control
7.4 Activating process control
If a valid reference curve was generated for a program (refer to Sec­
tion 7.3 from page 36), activation of process control is possible for this
program. 
 
1. Select the subtab "UIR" in the "Programming" topic, "PSQ" tab.
2. Select the corresponding spot name (1a) or timer and program num­
ber (1b).
3. Activate the process control.
To do this, you must -�in addition to the existence of a valid reference
curve�- set the „Measurement (S)“, „Measurement (P)“, „Regulation
(S)“ and „Regulation (P)“ parameters to „On“ (2).
The programs working with active process control are easily recog­
nizable in the „Overview“ topic using the „Regulation active“ option
button. Refer to Section 9.1.1 from page 76.
Information on the effects of the available parameters is provided in
the BOS online help and in Section 7.4.1 from page 49.
For information on the PSQ status display (3), refer to Section 9.1.2
page 77.
[1a]
3
1b
2 2
2 2
Fig.�17: Window „Programming“, „PSQ“ tab, „UIR“ subtab
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Commissioning of the process control
7.4.1 Description of the most important process parameters
Information on the effects of the available parameters is also
provided in the BOS online help.
Fig.�18: Window „Programming“, „PSQ“ tab, „UIR“ subtab, process parame­
ters
Which of the parameters described below in the „Programming“
topic, „PSQ“ tab, „UIR“ subtab are displayed, is dependent on the
user rights of the person logged in.
Measurement (�S)
OFF: the voltage measurement logic is deactivated for all programs of
the weld timer - irrespective of the Measurement�(P) parameter.
ON: the voltage measurement logic is activated for all programs of the
weld timer and can be switched on/off program-specifically using the
Measurement (P) parameter.
The activation of the force measurement is made in the chapter "Pro­
gramming",
Tab "PSQ", "Force" subtab, see chapter 5.3.2 page 22 .
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Commissioning of the process control
Expulsion current control (%)
Determines in combination with “Expulsion decay time” and “Detection
of expulsions” how the controller reacts to a detected expulsion. The
controller changes the current at the time of expulsion by the pro­
grammed percentage (+/- values are possible).
• 0: no current change
• positive value: current increase (in %)
• negative value: current decrease (in %)
Measurement �(P)
OFF: the voltage measurement logic is deactivated for the program dis­
played.
ON: the voltage measurement logic is activated for the program dis­
played - if it has been released timer-globally via Measurement (S). An
active measurement logic is the requirement for
• generating reference curves,
• displaying the current/voltage/resistance characteristic,
• process control and
• process monitoring.
Detection of expulsions (decrease) (%)
It is used in connection with the “Expulsion decay time” parameter to set
the expulsion detection and defines a force deviation (in %). 
As soon as a force value deviates from the previous measured value by
this % value, the system checks whether this also applies to all sub­
sequent measured values in the "Expulsion decay time". 
If that is the case, an expulsion event is initiated with a response accord­
ing to the "Expulsion current control" parameter.
Start expulsion detection manually (ms)
Period of time (in ms) from the beginning of MainWLD during which the
expulsion detection function is active. This time is not programmable in
PreWLD.
Weld counter
Number of spot welds carried out with the displayed program since the
last ”Delete”.
Can be reset to 0 using the ”Delete (P)” command button.
Expulsion counter
Number of expulsions which occurred during the welding process with
the displayed program since the last ”Delete”.Can be reset to 0 using the ”Delete (P)” command button.
The ratio of expulsion counter to weld counter is used to assess the
expulsion-related problems of this spot.
For the display of expulsion welds of all spots, refer to Section 9.4
page 80.
Measuring circuit test at
Defines the point in time of the respective measuring loop test (refer to
„Voltage „or „Force threshold“, beginning with the end of of SQZ.
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Commissioning of the process control
Voltage threshold
Defines the measured voltage at the time „Measuring circuit test at“ of
the measuring loop test at which the voltage measuring loop test is con­
sidered as passed.
Falling below the limit value causes welding operation to be aborted and
triggers the message „Abort measurement circuit Fault / Measuring cir­
cuit error“.
Force threshold
Defines the measured force at the time „Measuring circuit test at“ of the
measuring loop test at which the force measuring loop test is considered
as passed.
Falling below the limit value causes welding operation to be aborted and
triggers the message „Abort measurement circuit Fault / Measuring cir­
cuit error Force“.
Mode version
Aluminum:
Timer-global activation of the „process regulation and monitoring for alu­
minum spot welding“ option.
The behavior of the process regulation is adapted to the requirements of
aluminum spot welding tasks.
Steel:
Timer-global deactivation of the „process regulation and monitoring for
aluminum spot welding“ option.
The behavior of the process regulation is changed to „UI regulation“
Whether the respective process regulation for a welding program
should be activated/deactivated, is defined in the „Programming“
topic, „PSQ“ tab, „UIR“ subtab (refer to Section 7.4 page 48).
Detailed information on „UI regulation and monitoring“ is provided in a
separate document (for document number, refer to the table on
page 5).
Regulation (S)
OFF: Process control is deactivated for all programs of the timer - irre­
spective of the Regulation�(P) parameter. 
All spots are welded in PHA or KSR mode depending on the timer pro­
gramming.
ON: Process control is activated for all programs of the timer and can
be switched on/off program-specifically using the Regulation�(P) para­
meter.
Expulsion decay time
Serves in connection with the Detection of expulsions parameter for set­
ting of expulsion detection. It defines a number of consecutive force
measurements performed in a 1 ms cycle. 
As soon as a measured value deviates from the previous measured
value at least by the % value defined via "Detection of expulsions", the
system checks whether this also applies to all subsequent measured
values in the "Expulsion decay time". 
If that is the case, an expulsion event is initiated with a response accord­
ing to the Expulsion current control parameter.
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Commissioning of the process control
Regulation (P)
OFF: Process control is deactivated for the program displayed. 
The spot is welded in PHA or KSR mode depending on the timer pro­
gramming.
ON: Process control is activated for the program displayed provided
that all of the following conditions are met:
• Measurement�(S) and Measurement�(P) must be switched on
• Regulation (S) and Regulation (P) must be switched on
• the reference curve for the program displayed must be present and
valid (refer to PSQ icon on page 77).
Beginning of regulation
The value indicated is calculated automatically by the system when it
generates the reference curve for the current program and initiates the
beginning of various internal regulation processes.
Max. current increase (%)
Limits the maximum permitted current increase. 
The value refers to the current values of the program-specific reference
curve.
Max. current reduction (%)
Limits the maximum permitted current decrease.
The value refers to the current values of the program-specific reference
curve.
Weld time prolongation
• OFF: a prolongation of the weld time is not permitted.
• ON: the process controller may prolong the weld time automatically
if required. The “Max. weld time prolongation” parameter acts as limit
value.
Max. weld time prolongation (%)
The specified % value (max: 40%) refers to the length of the program-
specific MainWLD.
Presetting for common aluminium alloys: 40 %
Regulation gain positive
Influences the extent of the required current adjustment the process
controller works with in case of a current increase.
Presetting for common aluminum alloys: 50
Regulation gain negative
Influences the extent of the required current adjustment the process
controller works with in case of a current decrease.
Presetting for common aluminum alloys: 25
Regulation adjustment slope (%)
Influences the pos. and neg. controller gain during programmed slope. 
The programmed value is coupled with the positive and negative regu­
lation gain (regulation gain while slope = regulation gain * regulation
adjustment slope). Presetting for common alluminium alloys: 100 %
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Commissioning of the process control
max. waiting time for contact (ms)
Defines the maximum period of time (in ms) after the beginning of
PreWLD in which the contact (refer to „Threshold for contact“) between
electrode and sheet must be established.
If this period of time is exceeded or the end of PreWLD is reached
without contact being established, the system signals „Contact error“.
Contact threshold (%)
Basis for the contact monitoring is a resistance threshold. This threshold
is calculated from reference resistance values and to this refered con­
tact threshold. It defines in conjunction with „max. waiting time for con­
tact“ when the system recognizes a stable sheet to sheet contact.
If the contact resistance breaks down at the beginning of the weld
(sampling rate 1 ms) and fall below the threshold the system recognizes
contact and the welding process continues, otherwise the system is wai­
ting for contact.
Threshold force deviation PreWLD (%)
At the time of half PreWLD the timer compares the current force charac­
teristic with the reference force characteristic.
If the measured value at this time falls below the „Threshold force devi­
ation PreWLD“, the process controller will increase the current in the
second half of PreWLD by the „Current increase PreWLD“.
• Threshold force deviation PreWLD = 100%: no current change, func­
tion OFF
• Threshold force deviation PreWLD < 100%: current change (in%),
function ON
Current adaption PreWLD (%)
Current increase (in %) in conjunction with „Threshold force deviation
PreWLD“.
• 0%: no current change
• >0%: current increase (in%)
Monitoring (S)
OFF: process monitoring is deactivated for all programs of the timer - ir­
respective of the Monitoring (P) parameter.
ON: process monitoring is activated for all programs of the timer and
can be switched on/off program-specifically using the Monitoring (P)
parameter.
Monitoring (P)
OFF: process monitoring is deactivated for the program displayed.
ON: process monitoring is activated for the program displayed
provided that all of the following conditions are met:
• Measurement�(S) and Measurement�(P) must be switched on
• At least one of the monitoring functions under Programming / PSQ /
UIR monitoring must be switched on.
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Commissioning of the process control
7.4.2 Special features for activated process control
• Basic parametrization not permitted
Changes of program-specific basic parameters influencing perform­
ance are not permitted