Model 3010BR Hydrogen sulfide Analyzer
AMI
Analyzer Manual
3
Analyzer description:
Gas analyzers are divided into two main sections – the sample handling section, and the electronics,
including the software/user interface.
In any analyzer, the sample control is as important as the electronics. It selects the source of the gas to be
measured, controls its flow rate, and brings it to the sensor without allowing leaks or exposing it to
excessive tubing length (which slows the response of this kind of analyzer). AMI uses a version of the
patented “Cell block”, a machined block of nickel-plated aluminum that integrates all of these functions in
one compact, and reliable package. The sample enters the cell block through either the sample inlet, or
else the span inlet, with the selection made by a three-way valve. This valve is integrated with a needle
valve that controls the flow rate of either sample or span gas. Since the two valves are mounted together,
there are no opportunities for leaks or mis-assembly. The sample gas then passes through a flow meter,
and then across the face of the sensor via a defined flow path, exhausting through the vent. The sensor is
installed in a pocket accessible from the front of the unit behind a screw-in “Cell cap”, thus allowing sensor
replacement without tools or any sort of disassembly of the analyzer. All of these functions occur within a
single small block.
The electronics are divided into two sections. All of the user controls, the sensor and the display are
mounted in an easily-accessible NEMA box on the right of the assembly, while the power supply and the
safety components, along with the output circuitry are mounted in the small explosion-proof box to the left.
This allows complete control and maintenance when needed without declassifying the area or having to
open an explosion-proof enclosure. The analytical circuit is an “intrinsically safe” circuit that is absolutely
incapable of igniting an explosive mixture of gases even in the presence of two worst-case faults.
The NEMA 4 enclosure contains:
The measuring circuit board and the cell block.
A keypad that allows the user to perform all the normal adjustments required, such as alarm set
points, span, alarm bypass and output range selection.
A large LCD display that shows the H2S reading.
The circuit that measures the output of the sensor, and also measures the temperature of the
cell block, and calculates the H2S level.
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It sends this information digitally into the explosion-proof section on the left.
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It displays the alarm set points, and allows the user to adjust them.
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It displays the output range, which is also selectable.
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It can also display the cell block temperature.
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It displays the “span factor”. This is a useful number that gives an idea of how the
sensor is aging. You could think of it as the setting of the calibration dial on an old-
fashioned analog analyzer.
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The control panel also includes an “Alarm hold off” button. When calibrating the sensor
you normally do not want alarms to shut down the process or pipeline, and so you can
press this button to hold them off for a programmable delay time.
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In addition, it is possible to set up the analyzer so that casual users are not able to make
any adjustments, even though they can see what the alarm settings and the output
range are – they can be locked out of changing them.
The explosion proof box contains:
The safety barriers.
The output/relay PC board.