Watlow EZ-ZONE PM - Manual (Page 80)

Watlow EZ-ZONE ® PM Limit Controller • 77 • Chapter 8 Features
Resetting a Tripped Limit
Output 2 will always be a Form A (normally open) Mechanical Relay and it will always be internally tied to
the limit function. When the limit is in a safe state the internal coil for this relay will be energized, therefore
the relay will be closed. When a condition occurs that causes the limit to trip, the internal coil will deenger-
ize causing the relay to latch open. When the condition that caused the limit to trip has been resolved, the re-
lay will remain latched open until manually reset. The process to reset a latched limit can be different from
control to control and is dependent upon the controller firmware version.
To check the firmware revision of your control do one of the following:
1. Cycle power to the control while observing the number in the top display (this momentary numerical dis-
play reflects the current installed firmware version).
2. Navigate to the Factory Page by simultaneously pushing and holding the Advance Key ‰ and the Reset
Key
RESET
for approximately 8 seconds and then use the up or down arrow key to navigate to the Diagnostic
Menu. Once there, push the Advance Key twice where the revision [`reu] will be shown in the lower dis-
play and the upper display will indicate the current firmware revision.
Prior to firmware release 11.0:
1. Push the Reset Key
RESET
2. Configure a digital input with the Action Function set to Limit Reset (navigate to the Setup Page under
the Digital I/O Menu).
3. Use a field bus protocol, i.e., Modbus, EtherNet/IP, etc...where a value of zero would be written to the asso-
ciated address (navigate to the Operations Page and look for Limit Clear Request under the Limit Menu to
find appropriate address).
4. Cycle the power to the controller.
Firmware release 11.0 and above:
1. Push the Reset Key
RESET
2. Follow the steps below:
2a. Navigate to the Setup Page and then the Limit Menu
2b. Set Source Function A to the desired device that will reset the limit (Digital I/O or Function Key)
2c. Define the Source Instance
3. Use a field bus protocol, i.e., Modbus, EtherNet/IP, etc...where a value of zero would be written to the asso-
ciated address (navigate to the Operations Page and look for Limit Clear Request under the Limit Menu to
find appropriate address).
4. Cycle the power to the controller.
Alarms
Alarms are activated when the output level, process value or temperature leaves a defined range. A user can
configure how and when an alarm is triggered, what action it takes and whether it turns off automatically
when the alarm condition is over.
Configure alarm outputs in the Setup Page before setting alarm set points.
Alarms do not have to be assigned to an output. Alarms can be monitored and controlled through the
front panel or by using software.
Process Alarms
A process alarm uses one or two absolute set points to define an alarm condition.
Select the alarm type with Type [`A;ty] (Setup Page, Alarm Menu).
Alarm Set Points
The alarm high set point defines the process value or temperature that will trigger a high side alarm. It
must be higher than the alarm low set point and lower than the high limit of the sensor range.
The alarm low set point defines the temperature that will trigger a low side alarm. It must be lower than
the alarm high set point and higher than the low limit of the sensor range.
View or change alarm set points with Low Set Point [`A;Lo] and High Set Point [`A;hi] (Operations Page,
Alarm Menu).