Siemens ULTRAMAT 23 Product Information page 15

Probe purging function
Definition of purging function of 50 vpm probe
The maximum continuous concentration is 12.5 vpm. Although a measurement above such a concentration is still correct,
the probe is damaged by an exposure of more than 10 minutes. Therefore measurements above 12.5 vpm must be carried
out discontinuously and alternately with purging gas. The probe can be used for a measurement again following a purging
time of equal duration with air.
The function test is set during execution of the purging function in order to signal that the displayed value is incorrect.
How the purging function works
The purging function is triggered if the continuous measured value of H
concentration (12.5 vpm) in measuring mode for a period equal to the sample gas purge time.
The following occurs when the protection function starts:
● The last measured value is 'frozen' if the 'Analog outputs with FCTRL' parameter has been set to 'Hold', or
the current measured value is still displayed for all other settings.
● A "V" (H S purging function running) is displayed flashing in the measurement screen at the right edge where the test
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letter "!" appears (fault no longer pending logged).
● The zero gas value is opened
● The "Function test" status is set.
As long as the purging function is active, the zero gas valve remains open during the zero gas purge time. The device then
switches to the sample gas path. The function test (FCTRL) remains set and the test letter "V" flashes during the zero gas
purge time and the subsequent pre-purging phase. This signals that the displayed value is incorrect. The function test and
test letter are deleted following the pre-purging phase, and the current measured value displayed again. Monitoring of the
H S limit is already re-activated during the pre-purging phase.
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Return to measuring mode
An active purging function can be interrupted as follows:
● A value is reached below the maximum continuous concentration during the pre-purging phase
● Starting of the protection function
● Start a different state such as calibrate, AUTOCAL, etc.
Note
The analyzer continues to measure the gas concentration during execution of the purging function. You can read via
ELAN (k19) or PROFIBUS whether the analyzer is being processed, and in which step.
Supplement 1 for Operating Instructions C79000-G52xx-C216-03
A5E02769382-03, 03/2012
S is greater than the maximum continuous
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