8 • 65-2443 PPM Hydrogen Transmitter
Span Pot
The span pot is located to the left of the detector terminal strip (see Figure 2). Use a small flat blade
screwdriver to turn the span pot’s adjustment screw and adjust the amplifier’s full scale response
output during the calibration procedure.
Linearizing Pot
The linearizing pot (labeled LINEAR) is located in the bottom left corner of the amplifier (see
Figure 2). Use a small flat blade screwdriver to turn the linearizing pot’s adjustment screw while
applying mid-scale gas to linearize the transmitter’s output during the calibration procedure.
Test Points
The test points are on the right side of the amplifier (see Figure 2). The test points produce a 100 to 500
mV output that corresponds to the transmitter’s 4 to 20 mA output. Use the test points and a voltmeter
to measure the amplifier’s output during the start-up and calibration procedures. The black test point
on the bottom is the negative (-) test point and the red test point on the top is the positive (+) test point.
Junction Box
Use the junction box to install the transmitter at a mounting site that is remote from the controller. The
junction box also protects the amplifier and wiring connections made to the amplifier. Use the top 3/4
NPT conduit hub to connect wiring from the amplifier to the controller. Use the cover on the front of
the junction box to access the interior of the junction box. The detector and amplifier are factory
installed in the junction box.
