Technical data

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The PLC control program accepts the received input byte (PY 1).
The value of the GP byte at the time of the HDB execution (HDB receive
call with job number 211) is decisive. If a GP byte has changed its value
several times between two HDB executions, the current value is accepted.
This cycle overflow is indicated in the GP station list by the bus.
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With short PLC cycle times (< 50 ms) the HDB
SEND/RECEIVE calls with job numbers 210/211 may extend
the PLC cycle time. The load on the CP 5430 TF/CP 5431 FMS
may also increase so that the transmission times of the
global I/Os deteriorate. If you have short PLC cycle times,
make sure that the time between two HDB calls is greater
than 50 ms (e.g. by programming HDB SEND/RECEIVE calls
with job numbers 210/211 in every nth PLC cycle).
Sequence of the data transmission
The start-up OBs have the following task with the global I/Os data
transmission mode;
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They must synchronize the CP 5430 TF/CP 5431 FMS interface.
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They can make sure that the PLC only starts up when certain or all
stations are ready to transmit and receive (i.e. when there are no GP
error messages).
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If you have selected the CYCLE-SYNCHRONIZED update mode, the
complete GP should be received at the end of a start-up OB.
The SEND synchronization point is indicated by the SEND-HDB (ANR 210).
The parameter QTYP must be assigned the value "NN". DBNR, QANF,
QLAE are irrelevant. The ANZW should be assigned to a data or flag word.
The RECEIVE synchronization point is indicated by the RECEIVE HDB
(ANR 211). The remaining assignment of parameters to the HDBs is the
same as for the SEND synchronization point.
Communication with Global I/Os B8976060/01
Volume 1 9 - 14