Filter
Top Products
WATLOW Series 988 User’s Manual 7.7
Tuning, Manual Operation, Alarms and Error Codes, Chapter 7
Alarms
A rate alarm alerts the operator when the process monitored by input 1 is
increasing at a rate higher than the alarm high setting ( [A2HI], [A3HI] or
[A4HI] ) or decreasing at a rate lower than the alarm alarm low setting
( [A2LO], [A3LO] or [A4LO] ). The rate is sampled once a second.
Alarms can be latching or non-latching. When the alarm condition is
removed, a non-latching alarm automatically clears the alarm output and
alarm message, if one is present. You must manually clear a latching
alarm before it will disappear.
The alarm output is indicated by the corresponding LED on the front
panel: L2; L3; or L4. There may be an alarm message flashing in the lower
display, but if the [`Anun] prompt is set to [`OFF] (Global Menu), no
alarm message is displayed. When an alarm message is displayed, it alter-
nately flashes with the current prompt at a one-second interval in the
lower display.
To clear a latching alarm, first correct the condition then press the
Auto/Man key å once.
Alarm silencing is available with all alarms. This function overrides the
alarm on initial power up. On power up, the alarm message will not
appear and the appropriate L2, L3 or L4 LED and output will reflect a
non-alarm condition. Silencing is active until the process has entered the
safe region located between the low- and high-alarm settings. Then devia-
tion outside this safe zone triggers an alarm. If an alarm occurs at this
point, the output can be silenced by pressing the Auto/Man key å once,
but the controller still displays the alarm message.