Watlow F4T

Watlow F4T • 69 • Chapter 4 Application Examples
Process Alarm
In this example Universal Input 1 on module 1 measures the temperature of a chamber or ov-
en with a thermocouple. Alarm 1 monitors the temperature from the universal input which is
also used by the control loop as feedback for heat control. When the temperature goes out-
side the normal range defined by the user-adjustable, alarm set points, output 1 on module 4,
a form C relay energizes an audible alarm and an indicator lamp to get the operator’s atten-
tion.
Function Block Diagram
Application Tips:
• Alarm blocks are initially located in the library and can be dragged to the canvas.
• The signal from the universal input to IN on the alarm is the one the alarm monitors
against the alarm set point.
• The signal from the alarm to the output indicates when the alarm has occurred. The
alarm is indicated on the controller whether or not there is an output attached; the
output on the alarm block is for use with additional logic in the application diagram or
to drive external devices as is shown in this example.
• Enter names for blocks where possible to make the application easier to understand.