Sierra Monitor Corporation 4100 Series, 4100-36 specifications Specifications, How it Works

Model 4100 Series

Gas Sensor Modules

The Model 4100 Series Gas Sensor Modules monitor a variety of toxic and combustible gases and provide a 4-20 mA DC output signal of gas concentration

The Model 4100 Series utilizes semiconductor sensor tech- nology to provide monitoring of gases in the parts per mil- lion (PPM) ranges. These modules operate on 24 VDC input and have a non-linear 4-20 mA DC current loop out- put.

The four gas sensor modules in this series are:

4100-33 Gas Sensor Module 4-20 mA DC 4100-34 Gas Sensor Module 4-20 mA DC 4100-35 Gas Sensor Module 4-20 mA DC 4100-36 Gas Sensor Module 4-20 mA DC

These gas sensor modules can monitor a wide variety of gases. Table A provides a partial list of gases that can be reliably monitored. If your gas is not on this list, check with Sierra Monitor to determine if a 4100 Series gas sen- sor module is available to meet your requirements.

Also, these gas sensor modules can be calibrated with the gas of interest or with methane or carbon monoxide. Thus, the user does not have to obtain a special calibra- tion gas.

The Model 4100 Series provides a non-linear 4-20 mA out- put signal that can interface with the Sierra Monitor Sensys controller or other linearizing controllers / indicators. Curves and linearizing equations can be provided for a specific gas and sensor to enable the operation of these sensor modules with other brand controllers.

How it Works

Semiconductor sensors have a resistance in air that is affected by oxygen adsorbed on the surface of the sensor. Oxygen atoms capture electrons on the semiconductor surface, thereby increasing its resistance.

The sensors can be impregnated with dopants such that the sensor’s resistance changes when specific gases dis- place the adsorbed oxygen.

Nobel Metal Wire

Sensor

Heater Coil

Specifications

Sensor
Type:	Solid State Metal Oxide Semiconductor
Range:	20-500 ppm or 50-5000 ppm See Table A.
Response:	80% of concentration in less than 3 mins.
Typical Life:	1-3 years in Normal Service.
Detectable Gases And Vapors
Typical List:	See Table A

Maintenance

Calibration

Adjustments: Zero Adjust, Span Adjust

Sensor LED:	OFF indicates heater or film is an open circuit.
Environmental
Operating:	Temperature -10oC to +40oC (14oF to 104oF)
	Humidity 5% to 95% non-condensing
Storage:	Temperature -55oC to +85oC (-67oF to 185oF)

Electrical Data
Wiring:	3 wire non-isolated
Input Voltage: 14 - 30 VDC
Current:	70mA @ 4mA DC loop current;
	90mA @ 20mA DC loop current at 24VDC.
Power:	2.1 Watts
Output Range: 4-20mA DC Non-linear
Loop Res.:	800 ohms at 28VDC
Mechanical
Size:	6.75" x 4" x 3.5" (HxWxD)
	(17.1 cm x 10.2 cm x 8.9 cm)
Material:	Cast aluminum epoxy painted
Weight:	2 pounds (0.9 Kg)
Classification: Class I Division I Groups C,D
Mounting:	Connects to a vertical 3/4" electrical conduit

Sierra Monitor Corporation 1991 Tarob Ct. Milpitas, CA 95035 (408) 262-6611 800-727-4377 FAX: (408) 262-9042

Visit our Web site at: www.sierramonitor.com E-Mail: sierra@sierramonitor.com