Sending Data With Fb P_Snd_Rk (Active Request) - Siemens Simatic S7-300 CP 341 User Manual

Communication via Function Blocks
6.4 Using the Function Blocks with the RK 512 Computer Connection
6.4.1

Sending Data with FB P_SND_RK (Active Request)

The FB P_SND_RK function block can be used with parameter setting SF = 'S' to transmit
data from an S7 data area to a CP 341.
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 (LEN).
The LADDR parameter specifies the address of the CP 341 to be addressed.
The area of the data blocks is the only permissible source for data to be sent. The source is
fully specified by the data block number (DB_NO) and the offset (DBB_NO) of the first data
byte to be sent in this data block.
Permissible destination areas are data types (R_TYP) data blocks (DB), and extended data
blocks (DX). The destination is fully specified by the CPU number (R_CPU_NO, relevant only
for multiprocessor communication), the data type (R_TYP: DB or DX), the data block number
(R_NO) and the offset (R_OFFSET) at which the first byte is to be written.
The interprocessor communication flag byte and bit on the partner CPU are specified in
R_CF_BYT and R_CF_BIT.
The FB P_SND_RK function block can be called cyclically when the signal state at the R
parameter input is "1". This cancels the transmission to the CP 341 and places the
FB P_SND_RK in its initial state. Data that has already been received by the CP 341 is still
sent to the communication partner. If the signal state at the R input remains static at "1", this
means that sending is deactivated.
Error display at the FB P_SND_RK
The DONE output shows "request completed without errors". ERROR indicates whether an
error has occurred. If an event has occurred, the corresponding event number is displayed in
STATUS. If no error has occurred, the value of STATUS is 0. DONE and ERROR/STATUS
are also output in response to a RESET of FB P_SND_RK. The binary result BR is reset
after an error has occurred. If the block has been completed without errors, the binary result
has the status "1".
Note
The FB P_SND_RK function block does not have a parameter check. If the parameter
assignment is incorrect, the CPU can go to STOP mode.
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CP 341 Point-to-Point Communication, Installation and Parameter Assignment
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Manual, 09/2008, A5E02191071-01