Siemens FM 458-1 DP - BRCV Block-Oriented Data Reception Via an S7 Coupling

Communication blocks
2-20 Function Blocks - FM 458-1 DP
Edition 12.2004
2.3.4 BRCV Block-oriented data reception via an S7 coupling
BRC
V
Establish ready to receive
―
BO ENR PTR DW
―
Receive data is ready
Addressing parameters ID
―
W ID NDR BO
―
Status parameter NDR
Addressing parameters R_ID
―
DW RID LEN DI
―
Length of data received before
Maximum length, receive data
―
DI RLN CTR DI
―
Number of receive operations
ERR BO
―
Status parameter ERROR
STA W
―
Status, fault display
QTS BO
―
Block status
YTS W
―
Status display
The function block allows block-oriented data reception via a configured
S7 coupling.
The BRCV block receives data from a "remote" partner. The "remote"
partner is an SFB/FB, type BSEND (SFB/FB 12) on a SIMATIC S7-400
CPU.
After each data segment which has been received, an acknowledgement
is sent to the partner SFB/FB and the LEN parameter is updated.
The block is ready to receive when a "1" is connected to the control input
ENR. A running task can be interrupted with ENR=0.
The maximum length of the receive area is specified by the data at input
RLN. The length of the data block received is displayed at output LEN.
ENR Control parameter
The block is ready to receive with ENR = 1
Default: 0
ID Addressing parameter
Reference to the local connection description
(this is specified as a result of the STEP7 configured connection)
Initialization input,
Default: 0
RID The value at input RID specifies the association with the send SFB/FB.
The value at the input must match the R_ID parameter for SFB/FB on
the
send side. This allows several SFB/FB pairs to communicate via the
same logical coupling. The block pairs of a logical coupling, defined
using
RID or R_ID must be unique for this coupling.
Initialization input,
Default: 0
RLN The maximum length of the received data is defined here.
Only values of between 0 and 65535 may be configured.
Initialization input,
Default: 0
PTR The receive data, to be evaluated by the blocks for direct
communication,
is made available here (e.g. types DRD, DRD_I, etc.).
Default: 0
Symbol
Brief description
Mode of operation
I/O