Siemens SIMATIC MV500, Руководство по эксплуатации, Страница: 160 / 294

Process interfacing via an automation system (PLC, PC)
9.3 Control with Ident profile
SIMATIC MV500
160
Operating Instructions, 03/2021, C79000-G8976-C494-05
Table 9- 11 Memory area of the receive data (TXREF or RXREF)
Address Value Meaning
0x0000 0x01 "Program change" command identifier
0x0001 0x00 ... 0x0F Number of the program
Command: Read program number
You can prepare to read the current program number using the "Read program number"
command.
The MV command itself does not perform the actual read. Therefore, the data of the
"PHYSICAL WRITE" command only includes the MV command itself.
Before performing the "PHYSICAL READ" command, you need to execute the MV command
"Read program number" with the "PHYSICAL WRITE" command. If this receives positive
acknowledgment, you must then read out the actual program number with a "PHYSICAL
READ" command. You can find more detailed information on the "PHYSICAL READ" command
in the section ""PHYSICAL READ" commands (Page 165)".
The "PHYSICAL WRITE" command must specify the length "0x01" ("CMD_STRUCT.LEN_DATA =
0x01"); otherwise, the command receives a negative acknowledgment.
Table 9- 12 CMD_STRUCT
Parameter Value
CMD 0x71
OFFSETBUFFER 0x00
EPCID_UID 0x00
LEN_DATA 0x01
ADDR_TAG 0x00
Table 9- 13 Memory area of the receive data (TXREF or RXREF)
Address Value Meaning
0x0000 0x02 "Read program number" command identifier
Match string
Note
Sent match string takes effect immediately
A sent match string takes effect immediately. The sent match string is not synchronized with
the trigger signal or the processing of buffered acquired images.
Therefore, ensure that the match string is sent when no image acquisition is running.