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12-17 Combustible Gas Transmitter
12
O&M Manual
Rev-D
Figure 7 - Sensor/Transmitter Connectors, Controls and Test Points (ATI-0143)
TRANSMITTER ZERO
The transmitter zero is adjusted with the sensor exposed to air that contains no combustible gas.
Generally, the easiest method of zeroing the transmitter is to make the adjustment when you know that
the area is free of combustibles. Because it is normally necessary to check the area with a portable
combustible detector prior to removing the cover from the transmitter, the absence of an combustible
gases or vapors can be verified fairly easily.
The transmitter can also be set to zero using "zero air" available in cylinders. Zero air cylinders
and regulators are available from ATI or from specialty gas suppliers. Connect the zero air cylinder to the
calibration adapter and adjust gas flow to 500 cc/min. When the DVM stabilizes near 40mV, adjust the
zero potentiometer until the DVM reads 40 ± 0.5 mv.
NOTE: If using the ATI receiver display when adjusting the transmitter zero, place the receiver in
the "Inhibit" mode. When in the inhibit mode, the blanking around zero is disabled so that
the zero can be set accurately.
LEL Transmitter
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