Galvanic Applied Sciences 943-TGS-CE, Руководство по эксплуатации

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Revision 5 45 August 2021
3.4.5 Oven Cabinet Regulator
The oven cabinet instrument air regulator is normally set to 30 psig. However, the specific
value of this setting is not critical for system operation provided that the pressure is sufficient
to provide adequate sample aspiration, system zeroing, and effective back purge. In
situations where additional supply pressure is required, the regulator may be adjusted to its
maximum output of 50 psig without harming the analyzer.
As the control cabinet cooler draws significant flow of instrument air, it is
advisable to do all adjustments of the zero and aspirator drive air with the cabinet
cooler switched on, unless indepeandent air supply lines are used for the control
cabinet and the oven cabinet. In this fashion, deficiencies with the pressure and
/ or flow rate of the instrument air supply can be immediately detected.
3.5 Analyzer Outputs
The 943-TGS-CE analyzer generates both analog and digital output signals for connection to
the users’ plant control system. The analog output signals are used to output calculated
concentration and other pertinent analysis values, and are user-configurable for range, output
parameter, and output behaviour. The digital output (relay) signals are used for outputting
analyzer status signals.
3.5.1 Analog Outputs
There are four available analog outputs available on the 943-TGS-CE. The analog outputs
are all loop-powered 4-20 mA outputs which are fully user configurable for output parameter,
output range, and update behaviour when the analyzer is in back purge mode. Each analog
output can be configured to output one of the following parameters:
• Air Demand (range starts at negative full scale for 4 mA)
• H
2
S Concentration (% or PPM)
•
SO
2
Concentration (% or PPM)
•
COS Concentration (% or PPM)
• CS
2
Concentration (% or PPM)
• H
2
S:SO
2
Ratio
•
Sigma S (sum of H
2
S and SO
2
concentrations)
Each analog output can also be user configured to be either
Track
or
Hold
. Track and hold
refer to the behaviour of the analog output when the analyzer is placed in back-purge mode.
If an output is programmed to be Track, the output value will track along with the calculated
values when the analyzer is placed in back purge mode, and thus will go to zero (4 mA)
when the analyzer is in back purge mode. If an output is programmed to be Hold, it will hold
the last known good value from when the analyzer was in sampling mode and continue to
output this good concentration value until the analyzer goes back into sampling mode. Thus,
the analog output will NOT go to 0 (4 mA) when the analyzer is in back-purge mode.
Typically, an analog output configured to output air demand will be configured for Hold, while
concentration outputs are configured for Track, though this is entirely up to the user to
decide. The value output by each analog output is updated once per second. The
configuration of the analog outputs can be done either using the local display and keypad,
as described in Section 4.8.1, or by using the Web GUI, as described in Section 5.4.