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ALARMING AND DIAGNOSTICS
LEDs
The 20 LEDs on the face of the module provide a quick indication of the operating status of all four
temperature loops. An LED is provided for each loop to indicate when an Output is ON, Auto Tune is
ON, an Alarm condition is present or when heater burn-out has been detected. In addition, there are
Missing Terminal Block (TB), No External Power (24V), RUN, and OK LED indicators.
Alarms
The Temperature Controller alarms include, Low Alarm, High Alarm, Deviation Alarm, No Heater Current
Alarm (heater burn-out), Shorted Heater Output and Broken RTD or Thermocouple Alarm.
Low Level Diagnostics
The module performs both high and low level self diagnostics. Possible low level diagnostic errors
include, CPU Error, Firmware Error (Watchdog time-out circuit), Incorrect ROM Checksum, RAM Error,
and Analog Circuit Error. These errors are reported to PLC CPU in a slot dependent V-Memory location.
High Level Diagnostics
High level diagnostics include Loose Terminal Block and External Power Supply Failure diagnostic
errors. These errors are reported to the PLC CPU and identified on the module by LED indicators.
Loose Terminal Block and External Power Supply Failure diagnostic errors are reported to the DL405
CPU. An operator may use AUX 42 to determine the error type. Either error will also turn ON special
purpose coil SP45. V-Memory location V7762 will contain 0201 if the terminal block is loose. V7762 will
contain 0206 if no external power supply is present. V7760 specifies the base and module of the error
(0102 = Base 1 module 2).
1.2
INTRODUCTION
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