Operating Instructions
R
02/92
(PER:WST)
When an interrupt (process interrupt or interrupt) occurs the appropriate interrupt OB is called
depending on operating mode and jumper settings on the
1P
241.
Function block FB 157 is then called in the interrupt OB with the command BEF = KB.
Parameter ST indicates from which channel an interrupt was reported. The interrupt bits must be
evaluated each time FB 157 is called.
Bit O: channel 1
Bit 1: channel 2.
You can start your own interrupt program when a bit has signal status”1”.
A recommendation for interrupt
OB2
or FBO programming is shown in the example in sec-
tion 2.3.
If an interrupt occurs during processing of function block FB 157 in
the cyclic program, the grou interrupt at the bus is
cancelled
by
7
FB 157 (or by reading byte 7.
Consequently no interrupt identity bit can be evaluated in the alarm
OB.
In the function block,
howeve~
the control bits are updated, so that
depending on the interrupt identifier bits saved in the
fla
, your specific
f
interrupt program can be called. The information from w ich channel
the interrupt originated is stored in the control byte (ST).
Therefore after each call of FB 157 in the cyclic program, both
IP
241
interrupt bits must be scanned!
After being evaluated, the control bits in the interrupt OB must be
reset so that the interrupt programs
(FBxx
and
FByy)
are not processed
in the cyclic program again.
This is taken into account in the example in section 2.3.
2 – 16
IP
241 Equipment Manual
@
Siemens AG 1989, Order No.: 6ES5 998-0KD21
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
To Next Page
Loading...
Need help?
General
