Sierra Monitor Corporation 4501-05 - Manual (Page 6)

Model 4501-XX Toxic Gas Sensor Module
Page 2 of 35
Sierra Monitor electrochemical sensors provide improved reliability by allowing the gas to diffuse into the
sensor through a capillary port, rather than diffusing through membranes. The result is an extremely stable
sensor with very low temperature and pressure coefficients and the capability to monitor gas as ppm.
1.4 MECHANICAL
The sensor module is comprised of the following three primary components:
1.4.1 ENCLOSURE
Explosion proof, rain-tight aluminum or stainless steel electrical housing with three ¾” FNPT conduit hubs.
The enclosure cover has a viewing window. The 3 conduit hubs combined with the rotatable faceplate
enable the user to mount the module in a variety of configurations. See Figure 1-2 for details.
1.4.2 TRANSMITTER ELECTRONICS
Electronic Assembly consisting of one printed circuit board assembly mounted under a cover plate. Wiring
connections for power and signal interface are located on the back side of the display.
1.4.3 SENSOR ASSEMBLY
The sensor assembly includes a stainless steel, explosion proof, housing containing the gas sensor and a
wiring harness for connection to the transmitter. The sensor assembly threads into one hub of the
enclosure. The exposed end of the sensor assembly is threaded to allow connection of a rain-shield or
calibration gas delivery fitting.
1.5 INTERCONNECT WIRING
Not supplied with the sensor module, but necessary to the installation and operation is the two conductor
wiring shielded which connects the module to its power source and controller. Before this wiring is installed it
is important to read and understand the control system installation instructions to determine wiring
requirements and alternatives.
1.6 POWER REQUIREMENTS
The 4501-XX module operates on DC power between 14 VDC and 30 VDC. The DC power must be supplied
by the loop controller.
Figure 1 - 1: Model 4501-05 Aluminum Housing Gas Sensor Module Outline Dimensions