Sierra Monitor Corporation 4105 manual Product Description

1.PRODUCT DESCRIPTION

1.1 Introduction

Model 4105 Series Gas Sensor module features non- intrusive calibration, 4-20 mA output signal and local continuous display of the gas concentration in ppm (toxics), % LEL (Combustibles), or % vol (Oxygen). It is designed for use with industry standard control in- struments.

This manual provides instructions for 4105 series gas sensor modules that utilize common packaging and transmitter electronics with different sensors for de- tection of various gases. The full model number of the gas sensor module includes a suffix, 4105-XX, where “XX” is a number that identifies a gas type.

1.2 Application

The Model 4105-XX Gas sensor is intended for use in ambient monitoring applications. It is designed for fixed installation and for continuous operation.

Optional fittings and adapters can be supplied by Si- erra Monitor to provide continuous sample delivery to the sensor module.

1.3 Configuration

The gas monitor is comprised of a NEMA-7/4 enclo- sure which contains the transmitter electronics and a gas sensor which is installed in one of the two 3/4" conduit hubs.

5.42" 4.50"

2.81" 1.75"

		FAULT /KEYPAD
		MODEL 4105-02
		Combustibles % LEL
5.50"	Unity SPAN	ZERO
	Ph. 408-262-6611
	Milpitas, CA	7.25"
	CAL

Figure 1.2 Outline View - Gas Sensor Module

Instruction Manual

Figure 1.1 Model 4105 Gas Sensor Module

1.3.1 Electronics

When installed, the transmitter electronics will be con- nected to a power supply and control device via three wire cable.

The electronics provide a 4-20 mA current loop which is proportional to the full sensitivity of the sensor. Integral features include:

-L.C.D. readout of ppm of gas concentration.

-Magnetic switches for non-intrusive calibration.

-Visual indicators for fault condition.

-Electrical fault (0 mA) to controller.

The transmitter electronics assembly includes a printed circuit assembly and a cover plate which con- tains the L.C.D. readout and magnetic switches for calibration.

1.3.2 Sensor

The gas sensor cell is enclosed in a threaded housing and is plugged into a signal card located in the enclo- sure. This configuration allows for easy field replace- ment of the sensor cell.

Combustible: The gas sensor is a catalytic bead type.

Toxics & Oxygen: The gas sensor is an Electro Chemi- cal type.

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