PSB NG-SR-21-4-DDP Instruction Manual page 33

F. Heater Chamber Shutdown
A thermocouple (TE-6) is physically attached to heater housing. When housing
temperature rises above a fixed setpoint, the heater contactor opens. Blower
continues to run to cool housing down. This is a hard wired safety and PLC
monitors operation.
Input: TSHH temperature switch
Setpoint: 500°F
Action: Alarm light (2LT) ON; Heater turns OFF. Dryer operation continues;
Turning off Dryer Power switch resets alarm.
G. Thermocouple Failure
The PLC thermocouple module detects when thermocouple has opened. Alarm
stops operation until condition is corrected. A "No Response" alarm is activated
when TE4 or TE5 does not show an increase in temperature from ambient.
Input: Thermocouple module Open status bits
Setpoint: Fixed;
Action: Turn OFF Blower/Heater; alarm light (2LT) ON; Stop Regeneration
operation; Operator reset required.
H. RS-485 Communication Problem
Communication to thermocouple module is via RS-485. Failure of link will result in
dryer operating without current temperature data and loss of control.
Input: PLC communication port status bits
Setpoint: Fixed;
Action: Turn OFF Blower/Heater; alarm light (2LT) ON; Stop Regeneration
operation; Operator reset required.
I. Dewpoint
Dryer outlet moisture rising above setpoint triggers alarm. This alarm is
informational only.
Input: Temperature from ME1
Setpoint: -55°F
Action: Alarm light (2LT) ON; Dryer operation continues
NG-SR IOM 32 PSB INDUSTRIES