
4.4 Holding analog outputs of the SIO and avoid limit violation alarms
Any AM has
∙PROCESS
This variable is an
In the AM are some states depending from PROCESS.
∙"valid measurement" only if PROCESS = "valid sample gas".
∙holding analog outputs if PROCESS = "no valid sample gas"
∙watching limit violations is switched off if PROCESS = "no valid sample gas"
It's now the task of the system calibration to handle the variable PROCESS for any involved AM. This is done in the following way:
Any switching of a system valve looks if in the switched valves is a sample valve of any AM. If yes, then it sets PROCESS like follows.
sample gas | time delay | PROCESS- |
valve |
| variable |
switched off | - | sample not valid |
switched on | purge time of sample valve | sample valid |
It's very important to notice following:
SYSCAL only watches state of appropriate sample gas valve for setting of PROCESS- variable.
Any additional valve, serial to sample valve, which can switch off flow of sample gas can not be registrated for logic of
Supplement - 32 | NGA 2000 |
90003482(2)