Communication via Function Blocks
6.3 Using the Function Blocks
Point-to-point connection CP 440 Installation and Parameter Assignment
90
Manual, 09/2007, A5E00057742-03
6.3.1
S7 Transmits Data to a Communication Partner, 10 SEND_440 FB
How FB SEND_440 Works
The SEND_440 FB transfers a data field from a data block, specified by the DB_NO,
DBB_NO and LEN parameters, to the CP 440. The SEND_440 FB is called cyclically for data
transmission or, alternatively, statically (without conditions) in a time-controlled program.
The data transmission is initiated by a positive edge at the REQ input. A data transmission
operation can run over several calls (program cycles), depending on the amount of data
involved.
The FB SEND_440 function block can be called in the cycle when the signal state at the R
parameter input is "1". This aborts the transmission to the CP 440 and sets the
FB SEND_440 back to its initial state. Data that has already been received by the CP 440 is
still sent to the communication partner. If the R input is statically showing the signal state "1",
this means that sending is deactivated.
The LADDR parameter specifies the address of the CP 440 to be addressed.
长沙工控帮教育科技有限公司
www.gkbpx.com