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3
Operation
Troubleshooting
F
Electrical Interference
This sensor has been designed to be highly resistant
to EMI/RFI using multiple stages of filtering and
protection. However, in extreme environments, some
noise pickup can occur directly through the sensor.
Insure that the bare shield wire of the instrument
cable is properly connected at the readout unit. See
Figure 10, Note 2 for AirScan
Figure 10. Troubleshooting
ICSP Programming Port
Zero Adjust
Span Adjust
JP3
Note 1: Checking
ZERO
voltage to sensor
at +24 and GND
SPAN
24
VDC
Black
Red
-
+
SIG
+24
GND
SHLD
JP1
Note 2: Reading
signal at TEST+
TEST +
and TEST-
TEST -
40-200
mVDC
Black
Red
-
+
Manning AirScan-iR Refrigerant Sensor
continued
TM
iR meter test points.
Serial Port
Pushbutton S1
Rx LED
Tx LED
Pushbutton S2
JP2
S1
S2
Draw
Chamber
CALIBRATE
IR SOURCE
Tubing to
calibration point
19100 AirScan-iR-ind 05/2006 REVA Copyright © 2006 Manning Systems, Inc. All Rights Reserved.
Sensor On-board Diagnostic System
It is possible to have the mA output fail during
normal run mode. In some instances a mA output
circuit that is incorrectly setup can supply 4 mA to
the load reasonably well; however, an incorrect
circuit arrangement could not be capable of driving
20 mA to the load when required. Therefore, the
system will place a fault condition out on the mA
loop output and flash the "mA fault" LED indicating
the output wiring is not correct or load resistance is
too high.
To properly ensure the load is correct, during the 20
mA or (high) 4/20 mA integrity test, the output circuit
dynamic range is tested to its fullest extent. If the mA
fault LED blinks during this test, the load resistance is
too high or power supply voltage is too low.
In the case of a mA Failure during Run mode, the
"mA fault" LED will blink Fast.
In the case of a mA failure during the mA output test,
the "mA fault" LED will also blink Fast. See figure at
the top of the next page.
POWER
SYSTEM
FAULT
mA FAULT
ATMOS
ACTIVE
21
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