Servomex 07931001B, Operator'S Manual

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07931001B revision 6 © Servomex Group Limited. 2020
85
Purging gases are potentially harmful ensure adequate
ventilation is provided.
Before disconnecting the TU and RU from the calibration cell
ensure there is no risk from exposure to potentially harmful
gases.
Ensure the laser beam is switched off before disconnecting
the TU and RU from the calibration cell.
Note: We recommend that you use an absolute pressure sensor to measure
the gas pressure in the cell to provide the instrument with correct gas
pressure during the verification and calibration procedure. If a pressure
sensor is not fitted to the calibration cell, then a suitable blanking plug
should be used.
Note: If only the ambient pressure is known or the pressure sensor is located far
away from the cell, switch off the gas flow before calibration, wait for 1
minute for the readings to stabilize and then perform calibration. In this
case the gas pressure is equal to the ambient pressure
Note: If a temperature sensor is not available, the receiver temperature sensor
may be used as a proxy. Ensure system is thermally stable before
calibrating.
The transmitter and receiver should be connected to the calibration cell and be
purged with a none absorbing gas, usually nitrogen, via
Purge Port 1,
Measurement In,
ref Sections 2.2
‘and
2.3.
Ensure that Purge Port 3, ‘Enclosure Out’, is free to vent to
atmosphere.
After calibration is completed, the instrument must be returned to
the correct process settings including path length, pressure and
temperature.
Transmitter and Receiver purge ports should also be checked, so
that they are returned to the correct process and purge
requirements at installation.