Thyracont VSH88D, Руководство по эксплуатации

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4.4 Degas
Deposition or adsorbed gas molecules on the electrodes of the hot cathode
sensor may lead to increased degassing in ultrahigh vacuum or even cause
instabilities of the measurement signal.
In such cases it is appropriate to clean the anode of the sensor from such
deposited material and adsorbed gas molecules by degassing. This is done at
pressures below 2.0x10
-6
mbar by ohmic heating of the anode to temperatures
around 800°C.
Degas control by pushbutton
The degas function can be activated directly at the transducer by means of the
pushbutton, (see operating scheme in chapter 4.3). To do this first remove the
rubber cap above the ADJ pushbutton (1), then press the button several times by
means of a small screwdriver or similar tool (2) until the status LED starts
flashing quickly in red color. After 3s the degas process starts, signalized by a
slowly flashing red status LED. The degas procedure will end automatically after
approx. 3 minutes, but can be stopped anytime by a further keypress. Finally
insert the rubber cap again.
Degas control by analog signal
Degas can be started externally from a PLC simply by connecting Pin 9 to
ground for a short moment (see chapter 3.3.2).
The degas procedure will stop automatically after approx. 3 minutes, but can be
cancelled any time by again connecting Pin 9 to ground for a short moment.
While the sensor is degassing the red status LED is flashing slowly in red color.