Conair W1-1.5 User Manual page 83

OHMS
Temperature
transmitter board
+
black
red
Ohm
meter
Problem Possible cause
No reading No power to board.
Reading too low RTD wires shorted.
Improper range of trans-
mitter (too low).
Condensation on board.
Reading too high RTD opened.
Improper range of trans-
mitter (too high).
Condensation on board.
RF Interference Input power not clean.
UGH017/0500
VOLTS
Temperature
transmitter board
+ -
black red
Volt
RTD
meter
sensor
Solution
Check voltage at power supply. Measure volts across the +
and - of the power wires. Voltage should be 8 - 35 VDC.
Disconnect RTD before testing sensor resistance. Check
RTD with ohmmeter. Should be close to 100 ohms.
Disconnect black lead (-) and place current meter in series.
Check RTD with current meter. Current should be 4 -20
mA.
Inspect for condensation. Dry with hot air.
RTD opened. Disconnect RTD before testing sensor resis-
tance. Check RTD with ohmmeter. Should be close to 100
ohms.
Disconnect black lead (-) and place current meter in series.
Check RTD with current meter. Current should be 4 -20
mA.
Inspect for condensation. Dry with hot air.
Use twisted wires or shielded cable. RF resistant power
supply. Use a shielded cable to connect the sensor.
Connect the shield to ground. Encase the board in a RF
shielded enclosure.
Series 1 Portable Chillers, PLC Control
C
HECKING THE
T
EMPERATURE
T
RANSMITTER AND
RTD
CONT
RTD
+
Power
supply
T
ROUBLESHOOTING
'
D
CURRENT
Temperature
transmitter board
RTD
-
black
To
Current
Controller
meter
red
6-19