Thyracont VSI17D, Operating Instructions Manual

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VSI-de-170326
4.3 Switch-On / Switch-Off Cold Cathode
The cold cathode sensor can either be switched on manually or automatically.
The corresponding device parameter "Cathode Control Mode" (CM) can be set
by software command via RS485 interface, see also chapter 5.7.
With the cold cathode switched off the VSI will not provide pres-
sure readings. The analog voltage output will be 9.8V, via RS485
a related warning will be transmitted if applicable.
Manual Control
The cold cathode sensor must be switched on and off manually. This can be done
by software command "Cathode Control" (CC) or by means of a voltage signal
3…24VDC which has to be applied at pin 9 of the SubD connector.
It is also possible to invert the analog switch-on logic of the sensor by software
command "Cathode Control Logic" (DL), so that the sensor will be switched on
when a GND signal is applied at pin 9.
Automatic Control
The VSI vacuum transducer will automatically control switching on and off the
cold cathode sensor:
Switch-on pressure 2x10
-3 mbar
Switch-off pressure 3x10
-3
mbar.
For safety reasons and to prevent damage of the cold cathode
sensor it will in any case be switched-off as soon as gas pressure
increases 3x10
-3
mbar!