Technical data

Structure of the ZP station list
The station list has a length of 16 bytes, with each bit assigned to a station
address.
All stations configured for ZP and which respond correctly are marked with
"0". Stations not responding correctly or from which a diagnosis request
exists (only with IM318B) are marked with a "1" in the station list.
The last bit in the station list is irrelevant, since the permitted station
addresses on the L2 bus are in the range from 0 to 126.
Error bits and updating the station list during data transmission:
During start-up, the station list is initialized with "0". After the RECEIVE
HDB has been executed the first time, all stations which do not respond
correctly are marked with bit value "1". Note: the RECEIVE HDB is only
released when the complete polling list has been run through once.
As long as one station does not respond correctly, the corresponding group
error message is set both in the status word of the RECEIVE HDB (ANR
211) and in the status word of the ZP station list (ANR 202).
As soon as a station responds correctly, it is cleared from the station list
and the bit in the station list is set to "0".
15
76543 210
120 127
0
1
76543210
76543210
01234567
8 9 10 11 12 13 14 15
2 - 14
16 - 119
Byte
Bit
Station
address
Fig. 10.11: Structure of the ZP Station List
Communication with Cyclic I/Os B8976060/02
Volume 1 10 - 18