Technical data

SFCs for Distributed I/Os or PROFINET IO
System Software for S7-300/400 System and Standard Functions - Volume 1/2
16-16 A5E00709327-01
Function
The read job is executed asynchronously, in other words it requires several SFC 13
calls. The status of the job is indicated by the output parameters RET_VAL and
BUSY, also refer to Meaning of the Parameters REQ, RET_VAL and BUSY with
Asynchronous SFCs.
Parameter Declaration Data Type Memory Area Description
REQ INPUT BOOL I, Q, M, D, L,
constant
REQ=1: Read request
LADDR INPUT WORD I, Q, M, D, L,
constant
Configured diagnostic address of the DP
slave.
Note:
Addresses have to be entered in
hexadecimal format. For example,
diagnostic address 1022 means:
LADDR:=W#16#3FE.
RET_VAL OUTPUT INT I, Q, M, D, L If an error occurs while the function is
active, the return value contains an error
code. If no error occurred, the length of
the data actually transferred is entered in
RET_VAL.
RECORD OUTPUT ANY I, Q, M, D, L Destination area for the diagnostic data
that were read. Only the BYTE data type
is permitted. The minimum length of the
data record to be read or the destination
area is 6. The maximum length of the data
record to be sent is 240. Standard slaves
can provide more than 240 bytes of
diagnostic data up to a maximum of 244
bytes. In this case, the first 240 bytes are
transferred to the destination area and the
overflow bit is set in the data.
BUSY OUTPUT BOOL I, Q, M, D, L BUSY=1:
The read job is not yet completed.