Galvanic Applied Sciences 943-TGX, Operation Manual

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Revision 4 28 August 02, 2019
3.3.2 Digital Outputs
There are four (4) digital outputs available from the analyzer. The digital outputs are present
in the form of zero potential form C relay contacts. The digital outputs are isolated to 250
V
rms
. The
digital outputs
are provided to indicate analyzer operational status. The operational
status outputs are:
• Status (Fault / Normal)
•
Service (Warning / Normal)
•
Mode (Calibrate / Run)
• Control (Manual / Auto).
In addition to the 4 digital outputs associated with the analyzer operation, there is an
independent Purge Fail Alarm attached to the purge system.
a) Status (Fault / Normal) Indicator
The
Status (Fault / Normal)
output provides analyzer system readiness information.
Before ‘Normal’ status indication is given, the analyzer temperature zones and
spectrometer signal must be within the specific set point ranges. This indicator will be in
the ‘Normal’ state only when ALL of the following are true:
•
the analyzer is receiving mains power.
• the cell temperature is between the cell ‘Low Alarm’ temperature and ‘High Alarm’
temperature set points.
•
the probe temperature is between the probe ‘Low Alarm’ and cell ‘High Alarm’
temperature setpoints or the sulphur vapour signal is less than the High Svap alarm.
• the last spectrometer ‘Measure’ scan was within range.
•
the last spectrometer ‘Reference’ scan was within range.
•
the last spectrometer ‘Dark’ scan was within range.
The purpose of this indicator is to signify an analyzer problem. When this indicator is in
the ‘Fault’ state, the analyzer reverts to a ‘Back purge’ state. Should the fault causing
criterion clear, the analyzer will automatically return to ‘Normal’ status and start sampling.
b) Service (Warning / Normal) Indicator
The
Service (Warning / Normal)
output indicates when service is requested. This
indicator will be in the ‘Normal’ state unless one or more of the following is true:
• the control cabinet temperature is below 15ºC or over 40ºC.
• the spectrometer integration period is greater than 500 ms.
•
the peak value of the absorbance vector is greater than 2.0.
•
the sulfur vapour concentration is greater than 0.2%.
• the peak value of the raw scan during last zero is less than 2500 A/D (analog to digital)
counts.
The purpose of this indicator is to signify the analyzer is approaching the extremes of
optimum levels. When this indicator is in the ‘Warning’ state, the analyzer will NOT be
placed in the back purge mode. The analyzer will continue to function normally,
producing useable outputs. The analyzer will self-clear the ‘Warning’ condition and
automatically return to ‘Normal’ status once the offending parameter is found to be within
range.