© 2021 All rights reserved. Data subject to change without notice.
27
Rev. E | 2021.03
LPT - Operation Manual
7.3 Test Functions
During warm up and normal operation, the current loop and the voltage output can be tested by
using Jumpers on J2 (refer to Section
7.4 Jumpers
).
Plac
e the fi rst Jumper to set the gas output level (GAS3, GAS2, GAS1), then place the second Jumper
to the OVER pins. The current output will match the corresponding span gas level, and will remain
at that level for 5 minutes.
After 5 minutes, the unit will return to normal operation. Please return the Jumper placed on the
OVER location back to IDLE when testing is completed. (Refer to the table below for preset gas
levels).
Voltage Output to Test Points “TP-1” and “TP-2”:
NOTE:
This output is intended as a rough indication of the gas level and has not been precisely
calibrated.
Attach the meter leads to the two test points (TP-1 & TP-2) located on the lower left corner on the
back of the circuit board. Set the meter to volts DC with one decimal point. The range of 0 - 4.0
VDC is equal to the full measurement range of the sensor. Eg. HVAC CO sensor has a standard
measurement range of 0 - 200 ppm. Therefore 4.0 VDC = 200 ppm.
7.4 Jumpers
There are two jumpers on J2 located at the back of LPT PCA. These jumpers allow the user to
perform a range of set up, test and calibration functions.
The following table details the jumper settings and explains the function enabled when these
jumper positions are selected.
