Last fragment Host system
CP
Byte
Function
Byte
Function
t
0
0Ah Fragment-Info
1...15
User data byte 25...39
0
A0h Acknowledgement
u
0
4.4 Communication via handling blocks
For the processing of the connecting jobs at PLC side a user program is necessary in the
CPU.
With a System SLIO CPU use for communication FB 65 SEND_RECV.
The following VIPA specific blocks are used for communication between CPU, CP and a
communication partner:
Block
Symbol
Comment
FB 60
SEND
Block for data to be sent to a communication partner.
FB 61
RECEIVE
Block for data receipt from a communication partner.
FB 65
SEND_RECV
Block for data sent and data receive with a communication partner (e.g.
System SLIO CPU).
4.4.1 Overview
n
By a cyclic call of FB 60 SEND and FB 61 RECEIVE or FB 65 CP040_COM data may
be cyclically sent and received by the CP.
n
On the CP the transmission of the communication protocols to the communication
partner takes place, which may be configured by the hardware configuration.
n
A telegram to be sent is divided into blocks in the CPU depending on the IO size and
transferred via the data channel to the CP In the CP these blocks are assembled in
the send buffer, and when the telegram is complete, the telegram is sent by the serial
interface.
n
The exchange of received telegrams via the backplane bus is asynchronous.
n
If a complete telegram was received via the serial interface, it is stored in a 1024byte
ring buffer. From the length of the still free ring buffer the maximum length of a tele-
gram results.
n
Depending upon the parametrization up to 250 telegrams can be buffered, whereby
their overall length may not exceed 1024.
n
If the buffer is full, arriving telegrams are rejected.
n
A complete telegram is divided into blocks, depending on the parametrized IO size,
and transferred to the backplane bus.
Communication
Communication principle
VIPA System SLIO
Deployment
Communication via handling blocks > Overview
HB300 | CP | 040-1CA00 | en | 18-28
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