Fig. 23: Effect Of The Fade-Out Time - Bosch Rexroth PST 6 Serie Betriebsanleitung

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Information on this product
Fade‐out time and trail current
In the explanations made until now, an ideal temporal characteristic of
the current has been given (in rectangular form). However, current has
a transient characteristic at the beginning and the end of a weld time.
These effects in principle influence the effective value measurement.
As a result it may be necessary to program different values for setpoint
and reference current (in context with current monitoring).
Using the "Fade‐out time" and "Trail current" functions you can specifi­
cally influence the measurement sequence.
Parameter setting in BOS:
In "Programming", flag "General", parameter group "Current measure­
ment".
• Fade‐out time:
specifies the period of time after the start of a weld time which is not
to be used to calculate the effective value. If this is set correctly, the
entire transient procedure can be faded out.
Current
0
Fade‐out time
Irms_1: Fade‐out time taken into account
Irms_2: Fade‐out time not taken into account
Fig. 23: Effect of the fade‐out time
Use of fade‐out time
- in connection with the "Slope" function (refer to page 265).
program the same value for the fade‐out time as for the upslope
time (UST).
- for welding high sheet thicknesses and great immersion depths
(welding gun protrudes deeply into material).
- in connection with current calibration:
reference welding current measurement devices also have a
"fade‐out function" (e.g. Miyatchi: "First Cycle"; specification, from
which period of the weld time on the measured values are to be
taken into account).
With respect to current calibration, make sure that the measuring de­
"
vice you use is set to the fade‐out time currently parametrized in the
timer.
PST 6xxEx |
Weld time
1070087088 / 08
Irms_1
Irms_2
Time