Watlow Optimizing Your Process System with the Series 988 Controller - Manual (Page 43)

Standard Features
5.3
Optimizing Your Process System with the WATLOW Series 988
TL
TL
W WA
PROCESS
L1 L2 L3 L4
DEV
% OUT DISPLAY
MODE
AUTO
MAN
SERIES 988
temperature
sensor
Alarm
input 1 output 1
output 2
form C relay
Oven
heaters
The temperature is within the normal range.
Output 2 is inactive.
5-Silencing
Alarm silencing overrides the alarm at power
up, and it allows the operator to silence an
alarm with the system still in an alarm condi-
tion. The silencing is active until the process
has entered the safe region located between the
limit
limit
sensor
TL TL W WA
PROCESS
L1 L2 L3 L4
DEV
% OUT DISPLAY
MODE
AUTO
MAN
SERIES 988
Alarm
temperature
sensor
limit
sensor
input 1 output 1
output 2
form C relay
Oven
heaters
An over-temperature condition activates output 2,
which turns the alarm on.
limit
Sample Application
An operator is using a deviation alarm to keep a process within +/- 5
°F of
the set point. Output 2 is set up as a deviation alarm that activates a
buzzer. However, when the process powers up in the morning, the process
temperature is below the low deviation alarm set point, causing the buzzer
to sound until the process reaches the low alarm set point. Selecting ON
at the silencing prompt in the Output menu, disables the alarm
output controlling the buzzer until the process gets within the deviation
alarm set points. It also allows the operator to silence the buzzer by
pressing the AUTO/MAN key once, if an alarm does occur.
low and high alarm settings. Any future devia-
tion outside the safe region triggers an alarm. If
the alarm occurs at this point, the output can
be silenced by pressing the AUTO/MAN key
once, but the alarm message is still displayed.