Siemens SIMATIC MV500, Operating Instructions Manual, Page: 161 / 294

Process interfacing via an automation system (PLC, PC)
9.3 Control with Ident profile
SIMATIC MV500
Operating Instructions, 03/2021, C79000-G8976-C494-05
161
Requirement for matching with 1D/2D codes
All match options ("All", "Position", "ID", "GS1") are supported for 1D/2D codes. The match
string that is sent must be formatted in such a way that the information required for the
match can be extracted.
Command: Write match string
• This MV command allows the match string of the currently loaded program (non-
persistent) to be overwritten. This command can only be executed when the optical
reader is in processing mode. If the reader exits processing mode, for example by
changing to STOP mode or to the group error status, the overwritten match string is
discarded. This also applies to a program change.
• The structure of the memory area is outlined in the table below.
• The total length of the data to be written is the overall length of the match 3
bytes for the length and the command identifier ("CMD_STRUCT.LEN_DATA = n + 3").
• If the new match string is applied to the current program, the command receives positive
acknowledgment.
If the match string cannot be overwritten, an extra entry is made in the diagnostic data.
Table 9- 14 CMD_STRUCT
Parameter Value
CMD 0x71
OFFSETBUFFER 0x00
EPCID_UID 0x00
LEN_DATA Match string 3
ADDR_TAG 0x00
Table 9- 15 Memory area of the receive data (TXREF or RXREF)
Address Value Meaning
0x0000 0x03 Command identifier
"Write match string"
0x0001 0x00 ... 0xFF Length of match string high byte
0x0002 0x00 ... 0xFF Length of match string low byte
0x0003 -- 1st character of the match string
... -- ...
n + 2 -- (n-1)th Characters of the match string
n + 3 -- nth Characters of the match string