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Operating and service manual
113
Tusda 2 short
Warning
Description
USDA 2 Temperature Sensor Short Circuit
Cause
Indication of short-circuited USDA 2 temperature sensor
Trouble
shooting
Possible causes:
•
Temperature sensor Tusda2 or its cable defective.
•
X1 cable is defect.
•
Defective plug inside or cable on the unit backside.
•
Controller PCB defective.
Accompanied alarms:
•
N/A.
Trouble shooting:
1) Disconnect the sensor cable for sensor Tusda2 from the connector on the
interface/terminal block PCB, according to the wiring schematics inside in
the control cabinet.
2) Measure the resistance between the two wires.
a) If the resistance is less than (<) 230 Ω, the cable, the plug inside in the unit
or the sensor is defect. Check the plug before replacing sensor and cable.
b) If the resistance matches the resistance and temperature in table,
Tables
starting p.204, the temperature sensor and cable are ok.
3) Measure the voltage over the connector for Tusda2. It should be between
4.80 and 5.05V DC
a) If the voltage is inside the above range, connect sensor again. Measure the
voltage over the sensor and check voltage/temperature according to table in
Tables
starting p.204
b) If the voltage is outside the above range, the controller PCB is defect or
other sensors may be defect and pulling the voltage down. Check other
alarms and see
Trouble shooting for Star Cool Controller
p.56 before
replacing controller door.
Criteria
Value above high alarm limit +140°C (+284°F) and the sensor reading has been in the
valid area since power-up.
Controller
action
None
Log
X
Alarm
(X)
Alarm light
Off
Consequence
May be incomplete USDA data logging.
If activated Cold Treatment (CT), it will be affected
Elimination
When sensor value becomes valid, it is marked as inactive in the alarm list and may then
be deleted.
Log data
Parm 1
Parm 2
Parm 3
Parm 4
Parm 5
Active/Inactive Low limit
High limit
Present