Watlow F4T • 113 • Chapter 5 Function Reference
Direction Label Type Function
Transmitters
HT Analog % Heating needed: 0% is no heat and 100% is full heat.
CL Analog %
Cooling needed: 0% is no cooling and 100% is full cool-
ing.
PWR Analog %
Heating or cooling needed: -100% is full cooling, 0% is
no heating or cooling and 100% is full heating.
SP Analog
Set Point for use with Alarms or other blocks. Firmware
release 3.0 and above renames CSP to SP.
MP Analog %
Manual Power for use with other blocks. Firmware re-
lease 3.0 and above renames OSP to MP.
*Off Digital
Reflects the current state of "Control Mode Active":
Off = On, Auto = Off, Manual = Off
*Available in firmware release 3.0 and above.
Name
Uniquely identify this FB using up to 20 alphanumeric characters.
Control Action
Select to determine if control action will be heat, cool or both.
Options:
• Off: transmitters HT, CL and PWR are turned off.
• Cool: (also referred to as direct) as the process increase the output increases.
• Heat: (also referred to as indirect) as the process increase the output decreases.
• Both: heat and cool transmitters will be driven by the Cascade FB.
Heat Algorithm
Set the method the control loop uses to set heat (HT) and power (PWR) outputs. For a given
application, on-off switches the output less frequently than PID, whereas PID maintains the
process value with much less cycling around set point than on-off.
For applications other than temperature control, use the heat output when there is an indi-
rect relationship between the input and the output, that is when the output should be in-
creased as the input drops below set point.
Options:
• On/Off: On-Off control sets the HT and PWR to (100%) on, or off (0%)
To Next Page
Loading...
Need help?
General
