User guide

24 CDG100-OP-LIT (2010-1)
4.2.1 <ZERO> Adjustment
The zero can be adjusted via
• the <ZERO> button on the gauge,
• the digital input "Remote Zero" (briefly apply the
supply voltage (+14 … +30 V) to pin 10),
• the RS232C interface (→  [1]),
• a Nor-Cal Vacuum Gauge Controller.
While the gauge is being heated and/or under atmos-
pheric pressure, the zeroing function is locked in order
for operating errors to be prevented.
 Evacuate the gauge to a pressure according to the table
below:
F.S.
Recommended final pressure
for zero adjustment
1000 Torr
100 Torr
20 Torr
10 Torr
2 Torr
1 Torr
0.1 Torr
<5×10
-2
Torr
<5×10
-3
Torr
<1×10
-3
Torr
<5×10
-4
Torr
<1×10
-4
Torr
<5×10
-5
Torr
<5×10
-6
Torr
If the final pressure is too high for zero adjustment (>25%
of the F.S.), the zero cannot be reached and the
<STATUS> LED blinks green. If this is the case, activate
the factory setting and adjust the zero again (→  30).
 Operate the gauge for at least 90 minutes under constant
ambient conditions (until the signal is stable).