Siemens SIMATIC S5-100U System Manual page 265

S5-100U
Reading Out the Interrupt PII
If a process interrupt occurs, only the signal states of the interrupt inputs in slots 0 and 1 are read
out to the interrupt PII.
This data in the interrupt PII is the only data provided to the interrupt-driven program for evaluation.
The interrupt PII can be scanned in OB2 by means of the following load operations:
Overview:
Operation
L
L
L
If you enter other parameters, the CPU goes into the STOP mode and enters the "NNN" error
message in the ISTACK (see section 5.2). When data is read into the interrupt PII, the normal PII is
not written to simultaneously.
Writing to the Interrupt PIQ
Data from time-controlled or interrupt-driven programs to I/O modules are written to the interrupt PIQ
and simultaneously to the "normal" PIQ.
After OB2 is finished, the data that has been transferred to the interrupt PIQ is output to the
peripheral I/Os in an interrupt output data cycle (before "normal" program processing).
After the OB1 program cycle, the PIQ is copied to the interrupt PIQ.
The interrupt output data cycle is executed only if the interrupt PIQ has been written to. Use
transfer statements to write data for I/O modules to the interrupt PIQ. When data is written to the
interrupt PIQ, data is written simultaneously to the normal PIQ.
Overview:
Operation
T
T
EWA 4NEB 812 6120-02b
Operand
Load byte 0 of the interrupt PII into ACCU 1
PY 0
Load byte 1 of the interrupt PII into ACCU 1
PY 1
Load word 0 of the interrupt PII into ACCU 1
PW 0
Operand
Transfer contents of ACCU 1 into the interrupt PIQ
PY 0 to 127
Transfer contents of ACCU 1 into the interrupt PIQ
PW 0 to 126
Interrupt Processing
Description
Description
10-3