Issue
Programming an application that requires a setpoint and deadband that operates in the same manner as the WorkPlace Tech Tool Thermostat object.
Environment
- SmartStruxure AS or ES
Cause
No object exists in the Function Block library that is functionally equivalent to the I/A Series WorkPlace Tech LON/BACnet "Thermostat" object.
Resolution
This is only one of several methods by which a differential type thermostat object can implemented in Function Block programming.
The following Binary Expression (XPB) function block object can be used to simulate the differential type thermostat.
Analog Input A is the "Input"
Analog Input B is the "Setpoint"
Analog Input C is the "Input Differential"
Binary Input d is the "State Feedback" This feedback link insures that the output state does not change when the input is within the range specified by the input differential
The output of this object turns on when the Input value exceeds the Setpoint + 1/2 of the Input differential.
The output of this object turns off when the Input value falls below the Setpoint - 1/2 of the Input differential.
The xml file can be downloaded from here.
