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NGA-2000 System Calibration
Supplement - 32 NGA 2000 90003482(2) [NGA-e (MLT-Software 3.2.X)] 07/98
4.4 Holding analog outputs of the SIO and avoid limit violation alarms
Any AM has LON-variable:
• PROCESS
This variable is an input-variable. Its meaning is to tell the AM that another instance is not
allowing the measurement sample to flow valid.
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
valve
time delay PROCESS-
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 PROCESS-variable.