5
Functional description
Page 46
gas-lab
Q1
5.1.3 Test gas injection
The injection of test gases serves to check the gas quality meter with a known
gas or to measure unknown gases on a non-routine basis.
The following reactions of the evaluation computer are indicating the status of
the test gas injection:
Via measurement outputs and on the con
troller’s basic display the last
valid gas quality values are maintained provided any values are
available.
A
Revision
message will be generated.
Please proceed as described below:
1. Decide whether you like to inject the test gas via gas path 1 or 3.
2. Make sure the test gas cylinder is closed and the cylinder regulator is set to
zero. Set the associated precision pressure regulator to zero. Connect the
outlet of the precision pressure regulator to the first or third gas path of the
sensor system using a high-pressure tube. When using gas path 1, make
sure the process gas, which is also connected to this path, has been shut-
off tightly and thus is not able to affect the measurement by contaminating
the test gas.
3. Open the test gas cylinder. The cylinder regulator must be set to about
2 bars.
4. Set the precision pressure regulator to approx. 80 mbars.
5. Now purge the first or third gas path (see 5.1.5).