Watlow Series SD31 PID with Optional Countdown Timer - Manual (Page 63)

Wa t l o w S e r i e s S D 3 1
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C h a p t e r 1 0 F e a t u r e s
Indication Probable Cause(s) Corrective Action
Getting alarm message
[A1hi], [A2hi], [A1Lo], or
[A2Lo] . The process value is beyond an alarm set
point. Determine when alarms messages will display
and the proper response to an alarm message.
Alarm is occurring when it should
not. Alarm settings are incorrect. Adjust the alarm settings to be correct for the
application.
Input may be in an error condition. See error messages.
Alarm may be latched. Press the Infinity Key ˆ to unlatch an alarm.
Alarm output indication is incor-
rect. Alarm settings are incorrect. Adjust the alarm settings to be correct for the
application.
Alarm may be silenced. See the Features Chapter for information on
alarm silencing.
Alarm is not occurring when it
should. Alarm settings are incorrect. Adjust the alarm settings to be correct for the
application.
Output cycles (turns on and off)
too frequently. Wrong control mode. PID control selected in-
stead of On-Off control.
The cycle time is not set properly.
Select On-Off control mode ( [ht;m] or [CL;m]
Operations Page ) and set the desired hystere-
sis value.
Adjust the cycle time.
Controller does not control close
enough to the set point. Wrong control mode. On-Off control selected
instead of PID.
PID is not tuned properly.
Select PID control and perform tuning.
Run autotune or perform manual tuning.
Controller’s process value reading
is decreasing but actual process is
increasing. Thermocouple polarity is reversed. Check thermocouple connections. All thermo-
couple connections, including thermocouple ex-
tension wire, must maintain the correct polari-
ty for proper operation.
Analog voltage or analog current input scal-
ing is reversed or incorrect. Check the settings of the analog output scale
low and scale high parameter (Setup Page).
Parameter(s) do not appear. Parameter is not active. See Setup and Operation chapters to deter-
mine when parameters should appear.
Parameter lockout is active. Set the correct level of lockout for access (Set-
up Page).
Operations Page is not configured properly. Select the desired parameters for the Program-
ming Page.
Cannot access Operation Page.
Cannot change the set point.
Parameter lockout is active. Set the correct level of lockout for access (Set-
up Page).