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
22-21
22.10 Aborting an Existing Connection to a Communication
Partner within the Local S7 Station with SFC 74
"I_ABORT"
Description
With SFC 74 "I_ABORT," you terminate a connection that was established by SFC
72 "I_GET" or SFC 73 "I_PUT" to a communication partner in the same local S7
station. If the job belonging to I_GET or I_PUT is completed (BUSY = 0), the
connection resources used at both ends are released after SFC 74 "I_ABORT" is
called.
If the job belonging to I_GET or I_PUT is not yet completed (BUSY = 1), call the
relevant SFC again with REQ = 0 and CONT = 0 after the connection has been
aborted and then wait for BUSY = 0. Only then are all the connection resources
released again.
You can only call SFC 74 "I_ABORT" at the end where the SFC "I_PUT" or
"I_GET" is located (in other words at the client end).
The connection abort is activated by calling the SFC with REQ=1.
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.
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.
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.
BUSY OUTPUT BOOL I, Q, M, D, L BUSY=1: The connection abort is not yet
completed.
BUSY=0: the connection abort is completed.