Siemens SIMATIC MV500, Operating Instructions Manual, Page: 173 / 294

Process interfacing via an automation system (PLC, PC)
9.4 Control with FB 79
SIMATIC MV500
Operating Instructions, 03/2021, C79000-G8976-C494-05
173
Bit Signal Description
3 READ Processing result
Code was localized and decoded.
4 MATCH Processing result
Code matches the trained code.
5 N_OK Code was not legible.
6 - Current status of the trigger input
7 - Reserved
Note
Reading and processing analogous to the time diagrams
Writing the control byte and reading and evaluating the status byte must be performed in the
same way as in the time diagrams shown under "Select program".
Note
Using the FB79 with a very short trigger interval
When using the FB79 in combination with a trigger interval in which the distance of the
trigger signals corresponds almost to the image acquisition time, you should only use the
"DONE" bit of the FB79 for processing (not the "READ" bit or the "N_OK" bit).
"Send/Receive" user data interface
Table 9- 35 Send
Byte Description
0 Reserved
1 Consecutive number of the data packet to be transferred to the I/O controller.
2 Total net length of the data to be transferred in bytes in STEP 7 format.
3 --
4 Data ID of the supplied data
5 1st user data byte
... ...
31 27th user data byte
Note
Coding of the sent data
The "4 Data ID of the supplied data" byte defines the transferred data. The coding matches
byte 4 of the "Receive" user data interface. With a read job on the "Receive" user data
interface, the ID of the data currently being transferred is entered here.