Watlow EZ-ZONE
®
PM PID Controller • 82 • Chapter 9 Features
fect of analog, phase-angle fired control.
Select the AC Line Frequency [AC;LF] (Setup Page,
Global Menu), 50 or 60 Hz.
100 percent output
10 ON, 0 OFF
50 percent output
3 ON, 3 OFF
66 percent output
6 ON, 3 OFF
Note:
When output 1 is a universal process output, output 2 cannot
use variable time base, fixed time base only.
Single Set Point Ramping
Ramping protects materials and systems that can-
not tolerate rapid temperature changes. The value of
the ramp rate is the maximum degrees per minute or
hour that the system temperature can change.
Select Ramp Action [``rP] (Setup Page, Loop
Menu):
[`oFF] ramping not active.
[`Str] ramp at startup.
[StPt] ramp at a set point change.
[both] ramp at startup or when the set point
changes.
Select whether the rate is in degrees per minute
or degrees per hour with Ramp Scale [`r;SC]. Set
the ramping rate with Ramp Rate [`r;rt] (Setup
Page, Loop Menu).
Set Point
Time
Temperature
Heating System without Ramping
Temperature reaches Set Point quickly
Set Point
Time
Temperature
Heating System with Ramping
Te mperature ramps to Set Point at a set rate
degrees
per minute
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 auto-
matically 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 and Deviation Alarms
A process alarm uses one or two absolute set points
to define an alarm condition.
A deviation alarm uses one or two set points that
are defined relative to the control set point. High
and low alarm set points are calculated by adding or
subtracting offset values from the control set point.
If the set point changes, the window defined by the
alarm set points automatically moves with it.
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.
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