Handling with VIPA data handling blocks Manual BG41/BG42/BG43
4-56 Rev. 99/49
FORM
Transmission format: The command is a two byte command.
High-Byte 0 = Operation with the procedure 3964
1 = Operation with the procedure 3964(R)
Low-Byte Transmission format of the serial interface.
PRIO
Priority: Controls the telegram procedure by initialization conflict
0 = low priority
1 = high priority
BLOC
The block size indicates how many bytes are to be exchanged between the PLC
and the interface building block every time the data handling blocks
SEND/SEND-ALL, RECEIVE/RECEIVE-ALL, FETCH are loaded. The greater
the number of bytes to be exchanged, the greater the cycle time load.
The block size has no influence on the data transmission! The building block only
starts to output telegrams, when all data to be transmitted has been transferred
from the PLC to the building block.
The standard setting is a block size of 128 bytes. Only for "slow" PLCs e.g. CPU
941/942 is it sometimes necessary to set the block size to a smaller value, so that
the cycle time load is not too large.
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