Technical data

SFBs for Compact CPUs
System Software for S7-300/400 System and Standard Functions - Volume 2/2
28-46 A5E00739858-01
28.8 Deleting the Receive Buffer (ASCII, 3964(R)) with
SFB 62 "RES_RCVB"
Description
You can clear the entire input buffer of the module, using the SFB RES_RECV
(SFB 62). All stored telegrams are discarded. An incoming message frame is
stored when the SFB RES_RCVB is being called.
The job is activated after the block is called and at the positive edge on control
input REQ. The job can run across multiple calls (program cycles).
To enable the SFB to process the job, you must call it with R(Reset)=FALSE. At
the positive edge on control input R the delete process is cancelled and the SFB is
reset to basic state. A cancelled job is terminated with an error message (STATUS
output).
For your submodule, you declare the I/O address, which was specified by you in
"HW Config", in LADDR.
DONE is TRUE is the job was terminated without error, or ERROR is TRUE if the
job was terminated with an error.
In STATUS, the CPU indicates an error or, as a result of a warning, the respective
event ID.
DONE or ERROR/STATUS are also output when the SFB is RESET (R=TRUE).
The binary result BIE is reset if an error has occurred. The status of the binary
result is TRUE if the block was terminated without error.
Note
A parameter check is not included in the SFB. The CPU might jump to STOP mode
if the parameterization is faulty.
Instance DB
The SFB RES_RCVB operates in combination with an instance DB. The DB
number is passed on with the call. Access to the data in the instance DB is not
allowed.