Communications configuring
3-282 System- and communication configuring D7-SYS - SIMADYN D
Edition 12.2003
This pointer is actually a pointer which includes a structure, which in
addition to the pointer to the net data also has information for monitoring
purposes. This data includes, for example, the sampling time, block
class, byte/word swap. It has the connection comment "ZeigPuffer".
3.24.4.6 Configuring information and instructions
• The telegram blocks as well as the read/write blocks must be
configured in
the same sampling time in order to ensure consistency
(this is checked when initializing).
• Offset data must be carefully entered.
a) For pointer-based communications, the configuring engineer must
precisely observe the offset (in bytes) of the 16-bit value (INT) or 32-
bit value (REAL, DINT) to be addressed.
b) The offset must always be smaller than the buffer size.
Before accessing buffer data, a check is made as to whether the area
(range) has been exceeded because of an offset which has been set
too high.
• If data is transferred to a PROFIBUS-DP station or to a SIMATIC
CPU, then bytes (for INT) and, where relevant, words of the value to
be transferred (for REAL, DINT) must be swapped.
The read/write blocks have a "Swap" connection – SWP – for this
specific purpose.
• In order to transfer telegrams via an interface, initially, it is sufficient to
just configure the telegram block with the appropriate lengths data
(CRV_T, CTV_P and S7RD_P, S7WR_P). Read/write blocks still don't
have to be configured. This means that the interface can be tested or
the computation time load through the interface configured using, for
example, few resources.
3.24.4.7 Examples of CFC screenshots
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