Inficon PCG550 - ATM Setpoint, Diagnostic Port, and Fieldbus Operations

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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)
OffOnOff
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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 (→  59).