Watlow Series 922 - Manual (Page 39)

How To Program the Series 922, Chapter 6 39 WATLOW Series 922 User's Manual
Another feature of the Series 922 is its capability for up to eight event outputs via
an external event output board. You have the option of ordering your 922 without
events, or adding an external board for two or eight outputs. An "event output" is
simply a pre-programmed ON/OFF event per program step. The event may turn
any number of peripheral devices ON or OFF to assist you in controlling your
process, system or environment.
For instance, in an environmental chamber, you might wish to circulate air at a
given time in your program for one or more steps. You may want to turn lights ON
or OFF, or signals, lock out your humidifier, or activate a video recorder.
EV1 and EV2 are not visible under the SYSTEM menu until you select AUX1 &
AUX2 as events in the SETUP menu, and the two or eight event output board is
connected.
Enter the SETUP menu, and enter ACCESS (5). This is the SPCLFUNC (Special
Function) parameter. Press the MODE key until you reach the AUX1 parameter
and press ENTER. The default for AUX1 and AUX2 is AL (Alarms). Change the
value to EV (Events) if it hasn't already been done.
If you return to the SYSTEM menu, EV1 and EV2 are visible, and can be turned
ON or OFF from here. EV1 and EV2 can also be viewed under the SETPOINT
parameter in the PROGRAM menu. EV3 through EV8 are not displayed unless
you have the 8 event output board connected. See the Model Number Information
on Page 70 for ordering information.
If the events are programmed for one step and left unprogrammed for the next
step, the events maintain the last programmed status. These event outputs are
solid state relays rated at 0.5 amps up to 240VAC.
Guaranteed Soak
The Series 922 Guaranteed Soak (GS) feature insures that the process tempera-
ture tracks a programmed ramp. The Guaranteed Soak acts as a deviation alarm.
The program clock halts if the ACTUAL temperature exceeds the Guaranteed Soak
value. At this time the HOLD LED flashes. The clock starts once the process
variable is within the GS deviation value. Programmed in degrees or process units,
GS is in the SETUP menu under ACCESS (5). Entering a value of (0) disables the
Guaranteed Soak function. The Guaranteed Soak function only applies to
Channel 1. Figure 30 is an example of the Guaranteed Soak function.
Events/ GS
Time
Guaranteed Soak
Window Around
Set Point
Temperature
Programmed Ramp
Event Outputs
Figure 30 -
Guaranteed Soak
(GS) Example
NOTE: If the
program is put in the
HOLD mode while
holding for a
guaranteed soak,
and restarted at
another step, the GS
has to be met for the
previous step,
before the program
can continue.