Technical data

Table Of Contents
Open Communication via Industrial Ethernet
System Software for S7-300/400 System and Standard Functions - Volume 2/2
23-30
A5E00739858-01
Function
FB 64 "TRCV" is an asynchronously functioning FB, which means that its
processing extends over several FB calls. To start receiving data, call FB 64 with
REQ = 1.
The job status is indicated at the output parameters BUSY and STATUS. STATUS
corresponds to the RET_VAL output parameter of asynchronously functioning
SFCs (see also Meaning of the Parameters REQ, RET_VAL and BUSY with
Asynchronous SFCs).
The following table shows the relationships between BUSY, DONE and ERROR.
Using this table, you can determine the current status of FB 64 or when the
receiving process is complete.
BUSY DONE ERROR Description
TRUE irrelevant irrelevant The job is being processed.
FALSE TRUE FALSE The job was completed successfully.
FALSE FALSE TRUE The job was ended with an error. The cause of the error can be
found in the STATUS parameter.
FALSE FALSE FALSE The FB was not assigned a (new) job.
Note
Due to the asynchronous function of FB 64 "TRCV", the data in the receiver area
are only consistent when the NDR parameter assumes the value TRUE.