Fig. 27: Example: Principle Of Automatic Spot Repetition With "Max. Repetitions - Bosch Rexroth PST 6 Serie Betriebsanleitung

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Information on this product
Ç Ç Ç Ç Ç Ç Ç Ç Ç Ç Ç Ç Ç Ç Ç Ç Ç Ç Ç
Current too high...
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Current ok
Ç Ç Ç Ç Ç Ç Ç Ç Ç Ç Ç Ç Ç Ç Ç Ç Ç Ç Ç
Ç Ç Ç Ç Ç Ç Ç Ç Ç Ç Ç Ç Ç Ç Ç Ç Ç Ç Ç
:
Weld triggered by
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the automatic spot Current too low... / No current...
repetition.
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Welds
Fig. 27: Example: Principle of automatic spot repetition
with "Max. repetitions" =4
Automatic spot repetition can be activated or deactivated separately for
each welding program using the "Reweld" parameter.
When automatic spot repetition is activated, the timer is able to automa­
tically repeat a defective welding schedule 1x - starting with SQZ - when
the messages "Current too high..." or "No current..." are output. In this
case, the welding gun remains closed after the defective welding sche­
dule, and the programmed squeeze time, weld time and hold time will
run again.
If the repetition results in a correct weld, the welding system will conti­
nue its normal operation. If an error occurs again during the repetition,
this will lead to the respective message ("Current to low...", "No cur­
rent...").
It is a problem that bad fits or improperly placed electrodes may, in
extreme cases, provoke the repetition of each spot weld, if the spot
repetition has been activated. Conclusion: the cycle time increases
considerably, which may go unnoticed at first.
For this reason, the parameter "Max. repetition" (max. permitted conse­
cutive spot repetitions) is available.
An internal counter is always reset to 0 when a weld is successful the
first time. In return, it is incremented whenever the "Lower tolerance
band" is not reached and automatic spot repetition is active at the same
time.
The automatic spot repetition is only performed when the internal coun­
ter value is smaller than/equal to the parameter "Max. repetitions". If this
is not the case, the timer will generate the message "Series of welds
below lower threshold point".
Parameter setting in BOS:
In "Programming", flag "Schedule", parameter "Reweld"
In "Programming", flag "General", parameter "Max. repetitions"
Messages may optionally be defined as "Fault" or as "Warning".
While an event defined as "Warning" does not cause a blocking of
the timer, the occurrence of a "Fault" always requires a "Fault reset"
(refer to page 357) in order to start the next welding schedule.
PST 6xxEx | 1070087088 / 08
Upper tolerance band
(in %)
Reference current in kA
Lower tolerance band
(in %)
Message "Series of welds below
lower threshold point"