Reference Gas Monitoring With Pressure Switch; Checking Gas Paths For Leaks; General Information On Leaks - Siemens SIPROCESS GA700 Quick Start Manual

7.4.5

Reference gas monitoring with pressure switch

Note
No monitoring of measuring ability
The reference gas pressure switch only has a protective function for microflow sensors and
is not intended to monitor the measuring ability.
It only monitors that the reference gas pressure is at least 1 000 hPa above the sample gas
pressure.
Note
Excessive sample gas pressure
At the time of delivery, the pressure switch for reference gas monitoring is set to approx. 0.2
MPa (rel.). If the sample gas pressure has to be changed by more than ±150 hPa due to
process-specific requirements, the reference gas pressure also has to be changed by the
same amount. Only then is sufficient monitoring functionality of the pressure switch ensured.
To reset the pressure switching point of the reference gas pressure switch
• Contact the Service (Page 137).
• Have the pressure switching point of the reference gas pressure switch adjusted by a
Siemens technician or someone trained for this scenario.
Checking pressure switch for function
1. Increase the reference gas pressure until the pressure switch is triggered, meaning that
the switch contact opens.
2. Please ensure that the reference gas pressure is not more than 2 000 hPa above the
sample gas pressure.
The value when pressure is increasing (response pressure) is always higher than the value
when pressure is decreasing (release pressure). This so-called switching hysteresis of the
pressure switch is approx. 200 hPa.
7.5

Checking gas paths for leaks

7.5.1

General information on leaks

The analyzers may only be used if all the required gas inlet and outlet lines have been
connected prior to startup and tested with an overpressure for leaks and tightness.
The device operator is responsible for the required gas inlet and outlet lines.
Quick Start
Compact Operating Instructions, 05/2018, A5E31805656-06
Commissioning
7.5 Checking gas paths for leaks
79