Galvanic Applied Sciences 943-TGX, Operation Manual

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Revision 4 29 August 02, 2019
c) Mode (Calibrate / Run) Indicator
The Mode (Calibrate / Run) output indicates when a zero calibration or a manually
requested forced zero back purge is in progress. This indicator will be in the ‘Run’ state
unless one of the following is true:
• a clock triggered (auto) zero calibration sequence is in progress.
•
a manually requested zero calibration sequence is in progress.
•
the analyzer has been placed in the ‘Force Zero’ mode (manually).
•
the analyzer is not receiving mains power.
When this indicator is in the ‘Calibrate’ state, the analyzer is not measuring the process
tail gas. When, during a calibration sequence, the zero calibration adjustment is
complete, this indicator is held in the ‘Calibrate’ state for a period of time specified by the
Zero Hold Interval configuration parameter. This buffer period allows the analyzer to draw
process gas and commence measurement before clearing the ‘Calibrate’ indicator. At the
expiration of the Zero Hold Interval, this indicator returns to the ‘Run’ state.
d) Control (Manual / Auto) Indicator
The
Control (Manual / Auto)
output indicates the validity of the analog output signals.
When this indication is in the ‘Auto’ state, the analyzer believes that output data are real
and current measurements of the tail gas process stream. Under conditions where the
validity of the output data is suspect, the analyzer places the Control flag in the ‘Manual’
state. This indicator will be in the
‘Auto’ state
only when ALL
of the following are
true:
•
the Status indicator is in the ‘Normal’ state (
i.e.
no instrument fault).
• the Mode indicator is in the ‘Run’ state ( i.e. not in calibration).
• the computer’s On Line / Off Line switch in is the ‘On Line’ position ( i.e. not being
serviced).
• the analyzer is receiving mains power.
The purpose of this indicator is to signify when the analyzer outputs are suitable for use
as closed loop control inputs. When this indicator is in the ‘Manual’ state, no control
action should be taken on the basis of the analyzer output signals. This indicator is
generated on the basis of the other analyzer indicators, as well as the condition of the
manual ‘On Line / Off Line’ button on the display. The Control flag state is automatically
returned to ‘Auto’ once the offending condition (s) has cleared.
When in ‘Manual’, Track and Hold outputs are held.
e) Purge Fail Indicator
The
Purge Fail
indicator indicates the status of the analyzer’s safety purge. If the proper
purge pressure is maintained in the control cabinet, the Purge Fail Indicator will show
normal. If the purge pressure drops to an unsafe level, then the
Purge Fail
Indicator will
indicate a fault.