Communication via Function Blocks
6.3 Using the Function Blocks
Point-to-point connection CP 440 Installation and Parameter Assignment
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Manual, 09/2007, A5E00057742-03
6.3.2
S7 Receives Data from a Communication Partner, 9 RECV_440 FB
How FB RECV_440 Works
The RECV_440 FB transmits data from the CP 440 to an S7 data area specified by the
DB_NO, DBB_NO and LEN parameters. The RECV_440 FB is called cyclically for data
transmission or, alternatively, statically in a time-controlled program (without conditions).
With the (static) signal state "1" at parameter EN_R, the software checks whether data can
be read by the CP 440. An active transmission can be aborted with signal state "0" at the
EN_R parameter. The aborted receive request is terminated with an error message
(STATUS output). Receiving is deactivated as long as the EN_R parameter has the signal
state "0". A data transmission operation can run over several calls (program cycles),
depending on the amount of data involved.
If the function block detects the signal state "1" at the R parameter, the current send job is
aborted and the RECV_440 FB is set to the initial state. Receiving is deactivated as long as
the R parameter has the signal state "1".
The LADDR parameter defines the CP 440 to be addressed.
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