Knowledge Base:Heating

Simple Heating Setup by Mick Martin | Feb 28, 2012 | Knowledge Base

The client requested the following functionality,

Thermistor input to produce a 0-10 volt output to control a heating valve over a 4 degree centigrade band with the set point adjustable in software. Thermistor input to give a relay output with a set point adjustable in software. Input from others via software to give relay output for system on/off. Input from others via software to give 0-10 volt output to vary fan speed. Digital input to give a common fault signal to be sent via software to others. A BAS Remote controller from Contemporary Controls was specified and the inputs and outputs defined as follows,

Image SP1, SP2, Fan, Damper and Fault are all ModBus register addresses acces by a Trend Supervisor.

The follow diagram shows the logic strategy developed for the controller.

Image The control was wired in to a distribution unit and wall mounted in the plant room.