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VSM-de-171005
5.7 Readjustment
The transducer is adjusted ex works with 24V voltage supply in upright position,
flange to the bottom.
Other orientation, operation under different climatic conditions, extreme
temperature changes, ageing or contamination can result in the need for
readjustment of the Pirani sensor.
Adjust High AH
Adjustment of the Pirani sensor at atmosphere pressure
Adjust Low AL
Adjustment of the Pirani sensor at zero pressure. For this purpose actual
pressure must be less than 5,0x10
-5
mbar.
To achieve optimum results of the adjustment we recommend
to consider a warm-up of at least 10 minutes at the appropriate
calibration pressure before any adjustment.
5.8 Sensor Parameters
Sensor Transition (ST)
By default the VSM performs a continuous transition between Pirani and cold
cathode range whereupon an assimilation of the sensor signals is carried out.
In order to adapt the performance of the transducer to the requirements of the
vacuum process the following options can be configured via RS485 by means of
parameter "Sensor Transition" (ST):
"0": no transition, but direct switchover between Pirani and cold
cathode at 1.0 x10
-3
mbar
"1": (Default) continuous transition in the range 1.0 ... 2.0x10
-3
mbar
D[p]: no transition, but direct switchover between Pirani and cold
cathode at pressure p
F[p1] T[p2]: continuous transition in the pressure range p1 … p2
Value range p, p1, p2: 4 x 10
-4
… 2 x 10
-3
mbar
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