This means:
• With ASCII driver: The job was sent to the communication partner. This does not necessarily
mean that the data was received by the communication partner.
• With 3964( R ) procedure: The job was sent to the communication partner and acknowledged
armatively by the communication partner. This does not necessarily mean that the data
was forwarded to the partner CPU.
Jobs which can be processed simultaneously
Only one SEND_440 FB, one RECV_440 FB and one RES_RECV FB can be programmed in the user
program for each CP 440 used.
In addition, you can only use the following data blocks because the states required for the
internal execution of the FB are stored in the instance data block:
• 1 instance data block for the SEND_440 FB
• 1 instance data block for the RECV_440 FB
• 1 instance data block for the RES_RECV FB
Data Consistency
Please note the following to ensure consistent data transmission:
• Sender: Only access the send DB when all data have been completely transferred (DONE = 1).
• Receiver: Only access the receive DB when all data are received (NDR = 1). Then you must
inhibit the receive DB (EN_R = 0) until you have processed the data.
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 eld from a data block, specied 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 species the address of the CP 440 to be addressed.
Communication via Function Blocks
6.3 Using the Function Blocks
Point-to-point connection CP 440 Installation and Parameter Assignment
76 Equipment Manual, 03/2022, A5E00057742-AE
To Next Page
Loading...
