325.6610.17 - 20 -
3.2.1.3 Outputs
The output of the sensor/transmitter is wired directly to a terminal block in the receiver so care
should be taken that the sensor is correctly connected to the receiver (refer to section 2.4). If
the sensor/transmitter is connected incorrectly, no damage will occur but the LED indicator on
the sensor/transmitter will not light and the LCD display on the receiver will indicate “BAD ID”.
The output of the sensor/transmitter consists of two multiplexed frequencies which provide
information for ambient temperature and sensed gas concentration. Refer to section 7.4.2 for
additional information.
3.2.1.4 Power Consumption
Nominal power requirement for the sensor/transmitter is approximately 0.5 watts per
individual sensor.
3.2.1.5 Sensor Cross-Sensitivity
The sensor may also be responsive to gases in sampled air other than the target gas. The
degree of the sensitivity may cause an error in the concentration reading of the target gas.
Table 3-1 below shows the typical concentration errors to be expected when a chlorine sensor
is exposed to the indicated concentrations of “interference” gases.
Table 3-1 Gas Cross-Sensitivity Data
Sensor response to an instantaneous change of 50% relative humidity would be a chlorine
equivalent of approximately +/-0.5 ppm lasting for 2 minutes with no permanent effect. Longer-
term changes in relative humidity (>5 minutes) have no effect.
3.2.2 Receiver
3.2.2.1 Input Voltage
The receiver is designed to operate on any voltage between 93.5 and 276 Vac without the
need for the customer to make adjustments should he decide to change voltage sources.
The sensor/transmitter is powered by the receiver.
3.2.2.2 Power Requirements
Overall system power requirements range from 10 to 14 watts and varies depending on which
system features are activated. Optional backup power is available to provide power during
AC power losses. Battery life is at least 24 hours with all sensors and options active. Battery
charge is automatically maintained by the receiver and no operator intervention is required.
Gas Concentration
(ppm)
CF Equivalent
(ppm)
Carbon Monoxide 300 0
Hydrogen Sulphide 15 approx. -0.5
Sulphur Dioxide 5 0
Nitric Dioxide 35 0
Nitrogen Dioxide 5 approx. 5
Hydrogen 100 0
Hydrogen Cyanide 10 0
Hydrogen Chloride 5 0
Ethylene 100 0
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