Watlow F4T Install & Troubleshooting
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35
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Chapter 5 Troubleshooting
Indication
Description
Possible Cause(s)
Corrective Action
Limit High
Sensor input above
high limit set point
• Temperature is greater
than limit set point
• Limit outputs latch and
require reset
• Incorrect alarm set point
• Check cause of over
temperature
• Clear limit
• Establish correct limit
set point
Loop Open
Error
Open Loop Detect
is active and the
process value did
not deviate by a
user-selected value
in a user specified
period with PID
power at 100%.
• Setting of Open Loop
Detect Time incorrect
• Setting of Open Loop De-
tect Deviation incorrect
• Thermal loop or process
is open
• Open Loop Detect func-
tion not required but
activated
• Set correct Open Loop
Detect Time for applica-
tion
• Set correct Open Loop
Deviation value for ap-
plication
• Determine cause of
open thermal loop:
misplaced sensors, load
failure, loss of power to
load, etc.
• Deactivate Open Loop
Detect feature
Loop Reversed
Error
Open Loop Detect is
active and the pro-
cess value is headed
in the wrong di-
rection when the
output is activated
based on deviation
value and user-se-
lected value.
• Setting of Open Loop
Detect Time incorrect
• Setting of Open Loop De-
tect Deviation incorrect
• Output programmed for
incorrect function
• Thermocouple sensor
wired in reverse polarity
• Set correct Open Loop
Detect Time for applica-
tion
• Set correct Open Loop
Deviation value for ap-
plication
• Set output function cor-
rectly
• Wire thermocouple cor-
rectly, (red wire is nega-
tive)
Ramping
Controller is ramp-
ing to new set point
• Ramping feature is acti-
vated
• Profile is active
• Disable ramping feature
if not required
• Terminate profile if not
required
Autotuning
Controller is
autotuning the con-
trol loop
• User started the
autotune function
• Digital input is set to
start autotune
• Wait until autotune
completes or disable
autotune feature
• Connect the digital
input to function other
than autotune, if de-
sired
Anderson-Bolds ~ 216-360-9800
www.anderson-bolds.com
