Sierra Monitor Corporation 5000 Cover Plate - Ammonia Module, SMC sierra monitor corporation

SMC sierra monitor corporation Sentry Instruction Manual - Version 6

7.10 AMMONIA SENSOR MODULE (5100-25)

7.10.1 DESCRIPTION

The Ammonia Sensor Module includes a sensor assembly and electronic assembly installed in an explosion proof housing.

The sensor assembly includes a rechargeable electrochemical sensor. The assembly screws into one hub of the sensor module enclosure and plugs into the bottom electronics card via a six pin connector.

Cabling from the controller connects to a three pin spring loaded terminal strip on the electronics assembly.

7.10.2 TROUBLE ANALYSIS

Electrical adjustment, recharge, or replacement of the sensor will be necessary under the following conditions:

•Controller displays the following error messages

		SENSOR FAILURE
		LOW SENSITIVITY
									Figure 7-13
	• False readings or alarms are received
	due to sensor inaccuracy.							Cover Plate - Ammonia Module
Warning:		During sensor		adjustments		the
concentration reading on the				controller will		be		To make the electrical adjustment connect a voltmeter to
inaccurate		and	alarm level	concentrations		may	be
								SIGNAL OUT (pos) and GND (ground) and use SPAN ADJ
displayed.		If false activation		of	the alarm relays will
								potentiometer to adjust the voltage based on the
cause a problem			disconnect the		relay wiring prior		to
								following:
adjustment or turn the module off using the "Change
Module" mode.								•	1% of full scale = 0.02 VDC.
								• 100% of full scale = 2.00 VDC.
			NOTE
	Although all the necessary data can be collected with a
	voltmeter at the sensor module, some helpful information							7.10.3.2	SENSOR RECHARGE
	can be displayed on the controller or printed. See
	diagnostic codes 0004 and 0008 in Appendix C.							The Ammonia sensor can be recharged by removing it
7.10.3 ADJUSTMENT PROCEDURE								from service, draining electrolyte, cleaning electrodes and
								replacing the electrolyte and membrane.
Prior to reading voltages and making adjustments perform
								Step by step instructions for sensor recharge are supplied
a visual inspection to confirm that there are no physical
								with the recharge kit.
problems such as water in the electronics enclosure,
wiring damage or corrosion.

Use Figure 7-13 to locate test points during the following procedures.

7.10.3.3 SENSOR REPLACEMENT

The Ammonia sensor assembly should be replaced when it can no longer be recharged and calibrated correctly.

7.10.3.1 SIGNAL ADJUSTMENT

It is unlikely that any electrical adjustment will be required except when a new sensor is installed.

SERVICE

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