Watlow F4T User Manual

Watlow F4T • 123 • Chapter 5 Function Reference
point is 200° and Autotune Set Point is set to 90 percent, the autotune function utilizes 180°
for tuning.
Autotuning calculates the optimum heating and/or cooling PID parameter settings based on the
system's response. Autotuning can be enabled whether or not TUNE-TUNE+™ is enabled. The
PID settings generated by the autotune will be used until the autotune feature is rerun, the
PID values are manually adjusted or TRU-TUNE
®
+ is enabled. You should not autotune while a
profile is running. If the autotune cannot be completed in 60 minutes, the autotune will time-
out and the original settings will take effect. The temperature must cross the Autotune Set
Point five times to complete the autotuning process. Once complete, the controller controls at
the normal set point, using the new parameters.
To initiate an autotune, follow the steps below:
1. Determine and set the operational Set Point
2. Set the Autotune Set Point (a percentage of the Set Point)
3. Connect and activate a digital signal to TUN (appropriate active level is required)
If need be, there are settings provided to adjust the tuning procedure's aggressiveness. Use
Autotune Aggressiveness. Select Under Damped to bring the process value to the set point
quickly. Select over damped to bring the process value to the set point with minimal over-
shoot. Select critical damped to balance a rapid response with minimal overshoot.
Set to start or stop automatically tuning the control loop’s PID parameters. This parameter ap-
plies when either Heat Algorithm or Cool Algorithm or both are set to PID.
Options:
• No: if already started, aborts the autotuning process.
• Yes: initiates the autotuning process.
Initiate Autotune Active Level
Choose the signal value at the TUN receiver which causes the loop to start autotuning.
Options:
• High: the loop autotunes when the signal is on
• Low: the loop autotunes when the signal is off
TRU-TUNE
®
+
Enable
Enable or disable the TRU-TUNE+ adaptive tuning feature. This feature applies when either
Heat Algorithm or Cool Algorithm or both are set to PID.
Over time the TRU-TUNE+ adaptive algorithm adjusts the PID control parameters (Heat Pro-
portional Band, Cool Proportional Band, Integral and Derivative) automatically to optimize the
control loop’s responsiveness and stability.
Options:
• No: TRU-TUNE+ is off
• Yes: TRU-TUNE+ is on

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