Watlow Electric Ramping and Profiling Microprocessor-Based Control SERIES 1500 - Manual (Page 50)

Technical Reference
Alarm Display Codes
h in the FUNCTION display, indicating the type of alarm. These alarm messages are
listed below. The first two are operational alarms that have no effect on alarm/event
outputs.
A0 - Low RAM back up battery A5 - Ch - 1 Lower deviation exceeded
NOTE: Al - Power intenupt A6 -- Ch - 2 Upper Process exceeded
A2
An Al power
- Ch - 1 Upper Process exceeded A7 - Ch -2 Lower Process exceeded
interrupt alarm
A3 - Ch - 1 Lower Process exceeded A8 - Ch - 2 Upper deviation exceeded
A4 A9 -
will always flash
- Ch - 1 Upper deviation exceeded Ch - 2 Lower deviation exceeded
until an operator
presses the CLEAR
If more than one alarm condition is present, the lowest numbered alarm code will take
key (or sends
precedence. That is, if alarms Al and A6 are present, only Al will flash. If you clear
ALMOO), regardless
Al, then A6 will flash.
if aIarms are latched
or unlatched.
Alarm Results
What happens when an alarm occurs depends on how you have the auxiliary output
(Event #4) wired. The alarms by themselves don’t stop the Series 1500 program or
shut down the outputs.
The only alarm that has an effect on the Series 1500 program is “Al” - power
interrupt. If your unit has a battery-backed real time clock, and a short power
interruption occurs, the 1500 will pick up the program where it left off. The program
however, will be running behind the real time clock (correct time) by the duration of
the power outage. A “Waitfor" time step in the program would correct that time lag in
the next 24 hour period.
If your 1500 does not have a battery-backed clock and a short power outage occurs,
the 1500 still picks up on the step it left off, but both the real time clock and the
program will be running behind by the duration of the power outage. A Waitfor time
step will not re-synchronize the program and correct real time in this case.
Clearing Alarms
To clear the power intenupt alarm (Al, and alarms with the “latch” option, press the
CLEAR key in the MNTR DATA mode.
If an alarm condition is no longer present, the alarm will remain cleared. If the
condition is still present, the alarm message will reappear. In that case, you must
correct the condition that caused the alarm before it will clear.
Upper and Lower Set Point Limits are Display and Scroll
Limits, Not Alarms
The upper and lower set point limits, U1/L1 and U2/L2, are not alarms. They are
configured to limit the range of display and the scrolling capability of the Series 1500.
It is possible to have alarm points beyond the upper and lower limits of the control’s
set points.
50 WATLOW Series 1500 User's Manual
Alarms, Chapter 4