Watlow F4T User Manual

Watlow F4T • 107 • Chapter 5 Function Reference
• Auto: closed-loop control, the loop adjusts the outputs automatically to make the Pro-
cess Value equal to the Set Point
• Manual: open loop control, the loop's power outputs are set according to the Manual
Power setting
Note:
When a PID loop's Control Mode is changed from Manual to Auto, the Manual Power is set
equal to the integral value for a bumpless transition and normal PID action takes over to
control to the Set Point.
Control Mode Active
Displays the current method the control loop is using to set power outputs HT, CL and PWR.
Options:
• Off: power outputs are 0%
• Auto: closed-loop control, the loop adjusts the outputs automatically to make the Pro-
cess Value equal to the Set Point
• Manual: open-loop control, the loop’s power outputs are set according to the Manual
Power setting
Control Loop Error
Indicates the control loop’s error status.
Options:
• None: no error
• Open Loop: the process value has not responded to the loop’s outputs as expected ac-
cording to the settings of the Open Loop Detect Deviation and Open Loop Detect Time
parameters
• Reversed Sensor: the process value has responded to the loop’s outputs by changing in
the opposite direction expected, going down during heating or up during cooling
Clear Error
Set Clear Error to Clear to reset the Control Loop Error after correcting the condition that
caused the problem.
Options: Ignore, Clear
Compare
Use a compare block to set an output based on comparing two analog signals.
This block is found in the Function Block Diagram editor’s Library when working with a con-
troller that offers the Compare block. The number of these blocks that are available is shown
within the parenthesis.
Choose the type of comparison with the Function parameter. These options for the Function
parameter are described in detail in the following sections:
Off: the block’s output is off
Greater Than: the block’s output is on when input A is greater than input B
Less Than: the block’s output is on when input A is less than input B
Equal To: the block’s output is on when the two inputs are equal

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