92
• Temperature Measurement and Sensing Problems
An “EXHAUST DSFL” MESSAGE is displayed on the operator terminal any time a respective temperature
measurement has exceeded the programmed temperature in the PLC (Programmable Logic Controller).
A “DSFL” message will stop the current drying cycle and prevent a drying cycle from starting.
2. “EXHAUST DSFL” MESSAGE
a) PROBABLE CAUSES;
1a) Defective RTD (Resistive Temperature Device) Probe
2a) Defective 24 Volt DC Power Supply
3a) Defective Analog Input Module For Channel
4a) RTD (Resistive Temperature Device) Wiring To The “EXHAUST” 4 to 20 Milliamphere
(4 to 20 mA) Transmitter
5a) Circuit Wiring To the Analog Input Module
b) POSSIBLE SOLUTIONS;
1b) With the control voltage “OFF.”
The exhaust RTD
(Resistive Temperature Device)
probe can be quickly checked, by locating its
labeled disconnect in the right hand wire which is located on the main electrical enclosure panel.
Disconnect this plug and measure the resistance of the two wires coming from the RTD; it
should be
in the 100 ohm (100
Ω
) range.
•
If resistance is within range, wiring and RTD are OK.
•
If the resistance is infinite (no measurements), or zero ohms (1
Ω
) , go directly to the intake RTD
(Resistive Temperature Device)
disconnect box and measure the RTD’s resistance directly.
•
If the RTD resistance measurements is acceptable, check circuit wiring.
•
If the RTD resistance measurements is not acceptable; replace RTD and retest
2b) Defective 24 Volt DC Power Supply
With the control voltage “ON,” check that 120 volts AC is applied to the device’s AC input.
•
If no voltage check fuse #8, and wiring and retest.
Check that the device’s DC output indicator is “ON.”
•
If “OFF”, this indicates that there is no 24 volts DC output.
Disconnect the output voltage wires connected to the power supply and notice if the L.E.D. (light
emitting diode) indicator responds.
