Watlow F4T User Manual

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

Watlow F4T Specifications

General

Inputs	Thermocouple, RTD, mA, V
Outputs	Relay, SSR, mA, V
Communication	Ethernet, Modbus RTU
Data Logging	Yes
Certifications	CE, UL, cUL, RoHS
Control Modes	PID, On/Off
Power Supply	100 to 240 VAC
Operating Temperature	0 to 50°C
Enclosure Rating	IP65
Display	4.3 in. (109 mm) color touch panel LCD
Control Loops	Up to 4