Watlow ez-zone pm - Cool Output Curve; Resetting a Tripped Limit

Watlow EZ-ZONE
®
PMI Controller • 192 • Chapter 9 Features
Cool Output Curve
A nonlinear output curve may improve performance when the response of the output device
is nonlinear. If a cool output uses one of the nonlinear curves a PID calculation yields a lower
actual output level than a linear output would provide.
These output curves are used in plastics extruder applications: curve A for oil-cooled extrud-
ers and curve B for water-cooled extruders. Select a nonlinear cool output curve with Cool
Output Curve C.Cr (Setup Menu, Loop Menu).
Resetting a Tripped Limit
When a limit controller is ordered (PM _ _ _ _ _ - _ [L,M] _ _ _ _ _) output 4 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 de-energize causing the relay to latch open. When the condition that
caused the limit to trip has been resolved, the relay 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 rmware version.
To check the rmware 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 display reects the current installed rmware version).
2. Navigate to the Factory Page by simultaneously pushing and holding the Advance Key ‰
and the Reset Key
RESE
T
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 rEv will be shown in the lower display and the upper display will indicate
the current rmware revision.
Execute One of the Following Steps to Reset a Tripped Limit Prior to Firmware Release 11.0:
1. Push the Reset Key
RESE
T
2. Congure 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 eld bus protocol, i.e., Modbus, EtherNet/IP, etc...where a value of zero would
be written to the associated address (navigate to the Operations Page and look for Clear
Limit under the Limit Menu to nd appropriate address).
4. Cycle the power to the controller.
Actual Output Power
0
20
40
60
80
100
PID Calculation
Linear
Curve 1
Curve 2
Linear
Curve A
Curve B