PLC's first out Alarm routines
Chris Fletcher
Does anyone have an efficient routine written in ladder logic for first
out alarm annunciation? There are infinite ways to code this, I was
wondering if anyone had one they particularly liked. It should work as
follows.
The first alarm event that occurs turns on an alarm horn and
a corresponding fast flashing indicator. Any other alarms after that
just turns on a slow flashing corresponding indicator. An alarm
acknowledge silences the horn but the lights keep flashing, even if the
condition causing it has reset to a normal state. An alarm reset input
turns off all indicators whose causing event has reset, and all alarms
whose causing events have not reset change to a steady on indication.
You know, its your standard first out alarm sequence stuff.
Also can anyone point me to a web site or news group that is dedicated to
PLC programming?
TIA,
Chris Fletcher
sto...@ibm.net
Craig St George
>Does anyone have an efficient routine written in ladder logic for first
>out alarm annunciation?
>The first alarm event that occurs turns on an alarm horn and
>a corresponding fast flashing indicator.
Chris I have this logic the basic idea will be the same no mater what
type of PLC but the actual implemenation will be different on each
type. Mine is used on Modicon's. Basicly each alarm input sets a bit
in the current alarm Table this is compared with the alarm history
table and any new alrams are masked with the alarm flash. Once
accepted current alarm moves to alarm histroy. If the alarm is first
out it is detected and made to flash faster. Once accepted this alarm
stays flashing and the others go solid.
Randy Sweeney
(microsecond type) ordered logging of rapid fire cascaded alarms
like those found in big turbo generators.
VERY COOL and integrated into the PLC...
--
Randy Sweeney