Watlow Electric EZ-ZONE PM manual 69

Indication	Description	Possible Cause(s)	Corrective Action
[Li;h1] Limit High	Sensor input above high limit	• Temperature is greater than limit set	• Check cause of over temperature
[Li;h2]	set point	point
		• Limit outputs latch and require reset	• Clear limit
		• Incorrect alarm set point	• Establish correct limit set point
[LP;o1]	Open Loop Detect is active	• Setting of Open Loop Detect Time	• Set correct Open Loop Detect Time for
Loop Open Error	and the process value did	incorrect	application
	not deviate by a user-select-	• Setting of Open Loop Detect Devia-	• Set correct Open Loop Deviation value
	ed value in a user specified	tion incorrect	for application
	period.	• Thermal loop is open	• Determine cause of open thermal loop:
			misplaced sensors, load failure, loss of
			power to load, etc.
		• Open Loop Detect function not re-	• Deactivate Open Loop Detect feature
		quired but activated
[LP;r1]	Open Loop Detect is active	• Setting of Open Loop Detect Time	• Set correct Open Loop Detect Time for
Loop Reversed Error	and the process value is	incorrect	application
	headed in the wrong direc-	• Setting of Open Loop Detect Devia-	• Set correct Open Loop Deviation value
	tion when the output is	tion incorrect	for application
	activated based on devia-	• Output programmed for incorrect	• Set output function correctly
	tion value and user-selected
		function
	value.
		• Thermocouple sensor wired in reverse	• Wire thermocouple correctly, (red wire
		polarity	is negative)
[`rP1] Ramping 1	Controller is ramping to new	• Ramping feature is activated	• Disable ramping feature if not re-
	set point		quired
[tUN1] Autotuning 1	Controller is autotuning the	• User started the autotune function	• Wait until autotune completes or dis-
	control loop		able autotune feature
		• Digital input is set to start autotune	• Set digital input to function other
			than autotune, if desired
No heat/cool action	Output does not activate load	• Output function is incorrectly set	• Set output function correctly
		• Control mode is incorrectly set	• Set control mode appropriately (Open
			vs Closed Loop)
		• Output is incorrectly wired	• Correct output wiring
		• Load, power or fuse is open	• Correct fault in system
		• Control set point is incorrect	• Set control set point in appropriate
			control mode and check source of set
			point: remote, idle, profile, closed loop,
			open loop
		• Incorrect controller model for applica-	• Obtain correct controller model for ap-
		tion	plication
No Display	No display indication or LED	• Power to controller is off	• Turn on power
	illumination	• Fuse open	• Replace fuse
		• Breaker tripped	• Reset breaker
		• Safety interlock switch open	• Close interlock switch
		• Separate system limit control acti-	• Reset limit
		vated
		• Wiring error	• Correct wiring issue
		• Incorrect voltage to controller	• Apply correct voltage, check part
			number
No Serial Communi-	Cannot establish serial com-	• Address parameter incorrect	• Set unique addresses on network
cation	munications with the con-	• Incorrect protocol selected	• Match protocol between devices
	troller	• Baud rate incorrect	• Match baud rate between devices
		• Parity incorrect	• Match parity between devices
		• Wiring error	• Correct wiring issue
		• EIA-485 converter issue	• Check settings or replace converter
		• Incorrect computer or PLC communi-	• Set correct communication port
		cations port
		• Incorrect software setup	• Correct software setup to match con-
			troller
		• Termination resistor may be required	• Place 120 Ω resistor across EIA-485
			on last controller

Watlow EZ-ZONE®PM Integrated Controller • 67 • Appendix