7 – General operation
MultiExact Gas Analyser
7
GENERAL OPERATION
CAUTION
Sample and calibration gases must be as specified in Sections 2.4 and 2.5.
If the pressure/flow rates are outside the ranges specified in Sections 2.4
and 2.5, you must regulate the gases externally, before they enter the
analyser.
CAUTION
Before you allow sample or calibration gases into the analyser, you must
leave the analyser with the electrical supply switched on for at least:
•
4 hours, on an analyser without CO, CO
2
, N
2
O or CH
4
transducers.
•
24 hours, on an analyser with CO, CO
2
, N
2
O or CH
4
transducers.
If you do not, the gases may condense inside the transducer(s) and the
measurement will not be fully stabilised.
7.1
Checking the relay signal outputs
☞
Gas selection relays (sample, cal lo, cal hi) are not effected during the signal
relay override as this could cause hazardous gas flows.
If required, use the following procedure at any time to perform a check on the outputs
of the signal relays fitted to the analyser:
1.
Select
➞
Service
➞
Relay.
2.
Figure 89 shows the relay state
(energised or deenergised) that the
relay signals outputs will be set to
when the override is active. Edit if
required.
Figure 89 – The relay override
state screen
☞
When a relay is energised, the N/C-Common contacts will be open, and the
N/O-Common contacts will be closed. The converse is true when the relay is
deenergised.
74
05410001A / Revision 6
