Servomex 07931001B, Руководство оператора

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© Servomex Group Limited. 2020 07931001B revision 6
The reason for raising this status flag is safety related. If the cell is not purged
properly then on exit from auto validation it may still contain span-gas. This could
result in the analyzer producing an incorrect process measurement. There would be
no other fault or anything to let the user know that the measurement may not be
correct.
This status flag is persistent across power cycles. The only way to clear it is to run
another auto validation cycle. If at the end of the next cycle the cell measurement is
below the threshold, the status flag will be cleared.
Once the cell purge check has been completed, the analyzer will turn off baseline
subtraction. This will allow the normal process measurement to be re-established. It
takes several minutes for the measurement to return to normal as it is heavily
filtered and it takes time for a change in concentration to make its way through the
filters. So the analyzer will wait for a period to allow this stabilization to take place.
Note that the in-service flag remains active at this time so that any connected
system knows not to trust the measurement.
There is no involvement from the HMI in this stage.
At the end of this final stabilization time, the analyzer will automatically return to
normal operation and the in-service flag will be deactivated. An entry will be logged
in the status history saying that auto validation has been completed successfully.
Note that successfully completing auto validation is not saying whether the test
passed or failed. It is merely saying that the test procedure got through to the end
without being aborted or any fatal faults occurring.
In order to see whether auto validation has passed or failed there are two methods.