Thyracont VSH87D, Operating Instructions Manual

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»0«: no transition, but direct switch-over between Pirani and hot ca-
thode sensor at 4.0x10
-4
mbar
(hot cathode on at 4.0x10
-4
mbar / off at 6.0x10
-4
mbar)
»1«: continuous transition in the range 1.0 ... 2.0x10
-3
mbar
(hot cathode on at 3.0x10
-3
mbar / off at 4.0x10
-3
mbar) (default)
»2«: continuous transition in the range 2.0 ... 5.0x10
-3
mbar
(hot cathode on at 8.0x10
-3
mbar / off at 9.0x10
-3
mbar)
D[p]: no transition, but direct switch-over between Pirani and hot ca-
thode sensor at pressure p
F[p1] T[p2]: continuous transition in the range p1 ... p2
Value range: p, p1, p2: 4.0x10
-4
... 1.0x10
-2
mbar
Enable/Disable Hot Cathode - Cathode Control (CC)
For certain vacuum processes it may be favoured to suppress the automatic start
of the hot cathode sensor, which is usually controlled by the transducer electronics.
Therefore it is possible to disable the hot cathode by software comand »Cathode
Control« (CC):
»0«: hot cathode disabled, hot cathode sensor remains switched-off
»1«: hot cathode enabled, start of hot cathode sensor is controlled automati-
cally (default)
With disabled hot cathode sensor the VSH behaves like a Pirani transducer with
range 1000 - 1.0x10
-4
mbar. Below 1.0x10
-4
mbar the serial interface sends an
»UR« signal for pressure underrange, the analog output remains at a voltage cor-
responding to 1.0x10
-4
mbar.
The degas function cannot be started while the hot cathode sensor
is disabled.
Parameter »Cathode Control« is only temporarily saved in the
transducer memory. After mains supply is switched off or dis-
connected the VSH will always be reset to state »hot cathode ena-
bled«.
VSH-RS485-200116