Technical data

Table Of Contents
Communication SFCs for Non-Configured S7 Connections
System Software for S7-300/400 System and Standard Functions - Volume 2/2
A5E00739858-01
22-19
22.9 Reading Data from a Communication Partner within the
Local S7 Station with SFC 72 "I_GET"
Description
With SFC 72 "I_GET," you can read data from a communication partner in the
same local S7 station. The communication partner can be in the central rack, in an
expansion rack or distributed. Make sure that you assign distributed
communication partners to the local CPU with STEP 7. There is no corresponding
SFC on the communication partner.
The receive job is activated after calling the SFC with REQ=1. Following this, you
continue to call the SFC until the data reception is indicated by BUSY=0. RET_VAL
then contains the length of the received block of data in bytes.
Make sure that the receive area defined with the RD parameter (on the receiving
CPU) is at least as long as the area to be read as defined by the VAR_ADDR
parameter (on the communication partner). The data types of RD and VAR_ADDR
must also match.
Parameter Declaration Data Type Memory Area Description
REQ INPUT BOOL I, Q, M, D, L,
constant
Control parameter "request to activate," see
Common Parameters of the Communication
SFCs
CONT INPUT BOOL I, Q, M, D, L,
constant
Control parameter "continue," see
Common Parameters of the Communication
SFCs
IOID INPUT BYTE I, Q, M, D, L,
constant
Identifier of the address range on the partner
module:
B#16#54= Peripheral input (PI)
B#16#55= Peripheral output (PQ)
The identifier of a range belonging to a mixed
module is the lower of the two addresses. If
the addresses are the same, specify
B#16#54.
LADDR INPUT WORD I, Q, M, D, L,
constant
Logical address of the partner module. If it is
a mixed module, specify the lower of the two
addresses.
VAR_ADDR INPUT ANY I, Q, M, D Reference to the area on the partner CPU
from which the data will be read. Select a
data type supported by the communication
partner.
RET_VAL OUTPUT INT I, Q, M, D, L If an error occurs while the function is being
executed, the return value contains the
corresponding error code.
If no error occurs, RET_VAL contains the
length of the block of data copied to the
receive area RD as a positive number of
bytes.
BUSY OUTPUT BOOL I, Q, M, D, L BUSY=1: Receiving is not yet completed.
BUSY=0: Receiving is completed or there is
no receive job active.