Siemens SIMATIC S5 Manual page 131

Data Transmission Using Cyclic I/O
Status Byte for the ZP Master
Error codes Status codes
7 6 5 4 3
R R R R R
R = Read only
Figure 7-5. Structure of the Status Byte (STB) for the ZP Master
7-8
2 1 0
R R R
0: No ZPE cycle overflow
1: ZPE cycle overflow:
new ZP input data are available in DB ZP from all ZP slaves
although the CPU could not yet take over the previous ZP input
data .
0: No ZPA cycle overflow
1: ZPA cycle overflow:
The CPU has provided new ZP output data from the ZP DB to
the communications processor although previous ZP output data
could not yet be transmitted via the bus.
0: All ZP slaves transmitted the programmed number of ZP input
data.
1: At least 1 ZP slave did not transmit the programmed number of
ZP input data.
- If too many data were sent, the rest is discarded.
- If too few data were sent, the rest is filled up with "0".
0: ZP bus cycle is presently running.
1: A complete ZP bus cycle ended at the last ZP control point
(before this OB1 cycle)
slaves by the ZP master):
- The newest ZP input data are available from all programmed
ZP slaves and
- the ZP slave life list was updated in the communications
processor.
Bit 3 stays set for one PLC-CPU program cycle.
0: ZP data in ZP DB and ZP slave life list are valid.
1: ZP data in ZP DB and ZP slave life list are temporarily invalid;
previous ZP output data are being transmitted via the bus.
0: No ZP DB error
1: Programmed ZP DB is not available or ZP DB is too small; ZP
image in ZP DB is invalid, ZP output data
transmitted via the bus.
0: No ZP configuration error
1: One error minimum has occurred in at least one ZP slave:
- SAP not activated or parameter settings incorrect.
- ZP slave has insufficient or no receiving resources;
ZP slaves concerned are entered on ZP slave life list and their
ZP input area is set in ZP DB to "0".
0: All ZP slaves okay
1: At least one ZP slave has failed, is still in the start-up phase or
ZP master is still in the start-up phase; concerned ZP slaves are
entered in ZP slave life list and their ZP input area in ZP DB is
set to "0".
S5-95U, SINEC L2
(scanning of all the programmed ZP
EWA 4NEB 812 6112-02
"0" are being