Festo Кабели и принадлежности - Manual (Page 89)

4. Commissioning
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Festo P.BE−SPC200−COM−PDP−E N en 0901c
4.6.4 Reading and writing consistent data with the S7
In order that the parameter channel (PKW) can be used,
8Ăbytes of data (data consistency over the complete length)
must be transmitted consistently. With the Load and Transfer
commands of the S7, which access the peripherals or the
processing image of the inputs and outputs, maximum four
bytes can be transmitted together.
For consistent reading and writing of more than four bytes of
data, the system functions SFC14 (Read) and SFC15 (Write)
must be used on the S7. When using the parameter channel,
you must therefore use the system functions SFC14 (Read)
and SFC15 (Write).