Watlow F4T

Watlow F4T • 77 • Chapter 4 Application Examples
Compressor Control
In this example the temperature and humidity of an environmental chamber are controlled by
two loops. Loop 1 uses a heater to increase the temperature and a cooling coil to lower the
temperature. Loop 2 uses a solenoid to control water flow to an atomizer to raise the humid-
ity and a dehumidification coil to lower the humidity. The cooling and dehumidification coils
share a compressor. To minimize wear on the compressor and use of electricity, the compres-
sor is turned off and on by the controller’s Special Output function block configured for com-
pressor control.
Function Block Diagram