Watlow EZ-ZONE PM PID - Manual (Page 103)

Watlow EZ-ZONE ® PM PID Controller • 100 • Chapter 9 Features
Alarm Latching
A latched alarm will remain active after the alarm condition has passed. It can only be deactivated by the
user.
An active message, such as an alarm mes-
sage, will cause the display to toggle between
the normal settings and the active message in
the upper display and [Attn] in the lower dis-
play.
Push the Advance Key to display [ignr] in
the upper display and the message source in
the lower display.
Use the Up ¿ and Down ¯ keys to scroll
through possible responses, such as Clear
[`CLr]
or Silence [`SiL]. Then push the Ad-
vance ‰ or Infinity ˆ key to execute the ac-
tion.
See the Keys and Displays chapter and the
Home Page chapter for more details.
An alarm that is not latched (self-clearing)
will deactivate automatically when the alarm
condition has passed.
Turn alarm latching on or off with Latching
[`A;LA]
(Setup Page, Alarm Menu).
Alarm Silencing
If alarm silencing is on the operator can disable the alarm output while the controller is in an alarm state.
The process value or temperature has to enter the normal operating range beyond the hysteresis zone to acti-
vate the alarm output function again.
An active message, such as an alarm message, will cause the display to toggle between the normal set-
tings and the active message in the upper display and [Attn] in the lower display.
Push the Advance Key to display [ignr] in the upper display and the message source in the lower dis-
play.
Use the Up ¿ and Down ¯ keys to scroll through possible responses, such as Clear [`CLr] or Silence
[`SiL]
. Then push the Advance ‰ or Infinity ˆ key to execute the action.
See the Keys and Displays chapter and the Home Page chapter for more details.
Turn alarm silencing on or off with Silencing [`A;Si] (Setup Page, Alarm Menu).
Alarm Blocking
Alarm blocking allows a system to warm up after it has been started up. With alarm blocking on, an alarm
is not triggered when the process temperature is initially lower than the alarm low set point or higher than
the alarm high set point. The process temperature has to enter the normal operating range beyond the hys-
teresis zone to activate the alarm function.
If the EZ-ZONE PM has an output that is functioning as a deviation alarm, the alarm is blocked when
the set point is changed, until the process value re-enters the normal operating range.
Turn alarm blocking on or off with Blocking [`A;bL] (Setup Page, Alarm Menu).
Open Loop Detection
When Open Loop Detection is enabled [`l;de] , the controller will look for the power output to be at 100%.
Once there, the control will then begin to monitor the Open Loop Detect Deviation [`l;dd] as it relates to
the value entered for the Open Loop Detect Time [`l;dt]. If the specified time period expires and the de-
viation does not occur, an Open Loop Error will be triggered. Once the Open Loop Error condition exists the
control mode will go off.
Note:
All prompts identified in this section can be found in the Loop Menu of the Setup Page.
Normal Operating Range
Alarm High
Set Point
Time
Temperature
Alarm Low
Set Point
Alarm Response with Hysteresis
The alarm state continues until the
temperature drops to the Alarm High
Set Point minus the hysteresis. A
latching alarm could be turned off by
the operator at this point. A
non-latching alarm would turn off
automatically.
The alarm state begins when the temperature
reaches the Alarm High Set Point
Process
Temperature
Alarm Hysteresis