Michell Instruments QMA401, User Manual, Page: 23 / 102

QMA401 User’s Manual
Michell Instruments 13
OPERATION
3.2.1 Regulating Sensor Pressure
The sensor pressure of the QMA401 must match the pressure stated on the calibration
certificate in order for the calibration to be valid.
To control the sensor pressure, a pressure regulator is required on the input of the
analyzer.
An integral pressure regulator (rated to 300barg input pressure) can be supplied as an
option at time of order. Otherwise, when choosing an external pressure regulator, select
one designed for use in high purity gas, with a stainless steel body and diaphragm to
minimize impact on sample response speed when measuring dry samples.
To set the input pressure:
1. Power the analyzer on and wait for the oven to heat up before proceeding.
2. Navigate to the Monitor Screen.
Sensor pressure
shows the actual
pressure seen by the cell.
3. Use the pressure regulator to adjust the
Sensor pressure
to match the
pressure shown on your calibration certificate.
NOTE: The pressure at the outlet should be atmospheric, unless
otherwise stated on the calibration certificate.
4. Familiarize yourself with the menu system of the analyzer, and setup the
parameters listed in the next section. Before a measurement is made,
ensure the correct carrier gas has been selected in the menu system.