Watlow Series F4S/D - Manual (Page 20)

3 . 4 ■ O p e r a t i o n s Wa t l o w S e r i e s F 4 S / D
Alarm Set Points
The Series F4 includes two alarm outputs, which
can be programmed as process or deviation alarms.
Process alarms notify the operator when process
values exceed or fall below Alarm Low and Alarm
High Set Points. Deviation alarms notify the opera-
tor when the process has deviated from the set
point beyond the deviation limits. For more infor-
mation, see the Features Chapter. To set up the
alarms, see the Setup Chapter.
Alarm set points are the points at which alarms
switch on or off, depending on the alarm setting.
Alarm set points can be viewed or changed in the
Alarm Set Point Menus (Operations Page).
The Alarm High Set Point
defines the high tem-
perature that, if exceeded, will trigger an alarm.
This temperature 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 low tem-
perature that, if exceeded, will trigger an alarm.
This temperature must be lower than the alarm
high set point and higher than the low limit of the
sensor range.
✔ TIP:
You may want to set up the alarms with names that will
identify the alarm conditions. See the Setup Page.
To Clear an Alarm or Error
In an alarm condition, an alarm message will ap-
pear on the Main Page (if this option has been se-
lected on the Setup Page). To silence it, move the
cursor to the alarm message and press the Right
Key . . A pop-up message will confirm the silenc-
ing of the alarm, and the indicator light will go off.
When the condition causing the error or alarm is
corrected, return to the error or alarm message on
the Main Page, and press the Right Key again. A
pop-up message confirms the alarm is unlatched.
Auto-tune PID
In autotuning, the controller automatically selects
the PID parameters for optimal control, based on
the thermal response of the system. In the Series
F4, five sets of PID values are available for each
channel of the controller: sets 1 to 5 for channel 1,
and sets 6 to 10 for channel 2. Default PID values
exist for all PID sets, although these values typi-
cally do not provide optimal control. PID values
can be auto-tuned or adjusted manually. When au-
totuning is complete, the PID values will be stored
in the Edit PID Menu.
✔ NOTE:
PID Set 1 for Channel 1 and PID Set 6 for Channel 2
are used in the Static Set Point mode.
Autotuning Procedure
Autotuning cannot be initiated while a profile is
running. It can only be initiated in the static set
point control mode.
1. Before initiating auto-tune, go to the System
Menu (Setup Page), and set the Channel 1 or 2
Autotune Set Point to the percentage of set point
you choose to begin with. This percentage is
based on your knowledge of the system and how
much overshoot or undershoot there is likely to
be in on-off control.
In the Custom Main Page, select to display Tune
Status 1 and Tune Status 2. This displays Tune
Status in the Main Page.
2. Go to the Main Page and set the static set point.
3. Go to the Autotune PID Menu (Operations Page)
and choose the channel to auto-tune and the PID
set in which to store the settings. A message will
be displayed on the Main Page during the auto-
tuning process. (Auto-tune cannot be initiated
when a profile is running. It can only be initiated
in the static set point mode.)
4. When autotuning is complete, the controller will
store the values for optimum control in the PID
set specified.
✔ NOTE:
While the controller is autotuning, profiles cannot be run
and only the Profiles Page and Operation Page of the
software can be entered.
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CAUTION: Choose an auto-tune set point value that will
protect your product from possible damage from overshoot
or undershoot during the autotuning oscillations. If the
product is sensitive, select the auto-tune set point very
carefully to prevent product damage.
For additional information about autotuning and proportion-
al, integral and derivative control, see the Features Chapter.
Edit PID
Edit PID is useful when Auto-tune PID does not
provide adequate control. Each of the PID parame-
ters can be adjusted manually:
Proportional Band:
Define a band for PID con-
trol, entered in degrees or units. Lower values in-
crease gain, which reduces droop but can cause os-
cillation. Increase the proportional band to elimi-
nate oscillation.