INFICON PCG55x ATM to Medium Vacuum Gauge - Manual (Page 47)

tina56e1-d (2014-01) 47
4.4 ATM Setpoint
The setpoints SP1 and SP2 of gauges with separate atmos-
pheric pressure sensor
7)
can be programmed to atmospheric
pressure setpoint (ATM setpoint) via the diagnostic port or serial
interface.
The ATM setpoint is defined as a factor of the current atmos-
pheric pressure and can be set to any pressure within the meas-
urement range of the gauge. The relay switches when the pres-
sure in the vacuum system has reached the defined value.
Example: ATM setpoint: 110% of the atmospheric pressure
(= factor 1.1)
Switching characteristic: High Trip Point
Hysteresis: 10 mbar
1078 mbar
980 mbar
Atmospheric pres-
sure (ambience)
ATM setpoint 110%
(= factor 1.1)
Hysteresis (10 mbar)
Off On Off
M
eas
urem
ent value
Measurement signal
(Pressure p)
Threshold value
7 ) The atmospheric pressure sensor measures the atmospheric pres-
sure (pressure outside the vacuum system and can be calibrated
against the diaphragm capacitive sensor in the gauge (
→  60).