Technical data

Table Of Contents
S7 Communication
System Software for S7-300/400 System and Standard Functions - Volume 2/2
21-12
A5E00739858-01
21.5 Uncoordinated Receiving of Data with SFB/FB 9
"URCV"
Description
SFB/FB 9 "URCV" receives data asynchronously from a remote partner SFB/FB of
the type "USEND" and copies them into the configured receive ranges.
The block is ready to receive then there is a logical 1 at the EN_R input. An active
job can be cancelled with EN_R=0.
S7-300: The parameters R_ID, ID and RD_1 are applied with every positive edge
on EN_R. After a job has been completed, you can assign new values to the R_ID,
ID and RD_1 parameters.
S7-400: The receive data areas are referenced by the parameters RD_1 to RD_4.
You must, however, make sure that the areas defined by the parameters
RD_i/RD_1 and SD_i/SD_1 (at the corresponding partner SFB/FB "USEND") agree
in:
Number
Length and
Data type.
Successful completion of the copying process indicated at the NDR state
parameter by a logical 1.
The parameter R_ID must be identical at both SFBs/FBs.
Parameter Declaration Data Type Memory Area Description
EN_R INPUT BOOL I, Q, M, D, L,
constant
The enabled to receive control
parameter signalizes that the unit is
ready to receive when the input is set
ID INPUT WORD M, D, constant Addressing parameter ID, refer to
Common Parameters of the SFBs/FBs
and SFCs/FCs for S7 Communication
R_ID INPUT DWORD I, Q, M, D, L,
constant
Addressing parameter R_ID, refer to
Common Parameters of the SFBs/FBs
and SFCs/FCs for S7 Communication
NDR OUTPUT BOOL I, Q, M, D, L NDR status parameter:
0: Job not started or still running
1: Job has been executed error-free