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Deployment
Communication with the user program
Data consistency
Communication principle
32
The data consistency is limited by the block size of 32byte during communication
between CPU and CP. For the consistent data communication of more than 32byte the
following is to be considered:
n
FB 8 - P_SND_RK:
–
Access the send DB only again if the data were completely transferred
(DONE = 1).
n
FB 7 - P_RCV_RK:
–
Access the receive DB only again if the data were completely received (NDR = 1).
After that the receive DB should be blocked (EN_R = 0) as long as the data were
treated.
By a cyclic call of FB 7 and FB 8 data may be cyclic sent and received by the CP. On the
CP the transmission of the communication protocols to the communication partner takes
place, which may be configured by the hardware configuration.
More information about the usage of these blocks may be found in the
manual "SPEED7 Operation List" from VIPA.
VIPA System 300S
HB130 | CP | 341-1CH01 | en | 18-40
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