Appendix B: Heating Application Example - Extech Instruments 48VTR User Manual

Appendix B: Heating Application Example

Controlling Oven Temperature
•
The controller input (thermocouple), control output relay, and alarm relay are wired to
the process as shown in the accompanying diagram.
•
The controller is configured per the Programming Menu instructions below.
•
The user adjusts the setpoint (SV), using the arrow keys, to the desired oven
temperature (500
•
The thermocouple senses oven temperature and displays it on the front panel (PV).
•
The controller output switches the heater ON/OFF, as needed, to maintain the setpoint.
•
If the oven temperature reaches the alarm setpoint, the alarm relay triggers an alert as
shown. Note that you could wire the alarm relay in series with the control relay, as
shown in the Event/Soak Timer section, to shut down a process in case of emergency.
3rd Menu Level Parameters
• A1Fu (Alarm Function): Set to '2' (High Process Alarm). The Alarm relay will trip when
the temperature reaches 600
• Act (Action): Control output action. Set to '1' for heating.
• unit: Set to '1' for
• dp (decimal point): Set to '0' for no decimal point.
• Ct (Cycle time): Set to the longest time possible without causing process oscillations.
• tYPe: Set the thermocouple input type.
A1SP (Alarm Setpoint) in 1st Menu Level
Set the alarm setpoint to 600
Tuning the Controller (2nd Menu Level)
Run an Auto Tune session per the Auto Tune section instructions.
o
F for example).
o F and trigger the over-temp alert.
o F.
o
F to prepare the over-temp alert.
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48VTR User Manual v6.0 10/1/20