Write Match String - Siemens SIMATIC MV440 Operating Instructions Manual

10.6.3

Write 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 image acquisition.
• Therefore, ensure that the match string is sent when no image acquisition is running.
Requirements for matching with OCR
Sending a match string with OCR
Sending a match string is only possible if, in "2. Filter", the source "Filter with match text" or
"Character type at pos." is configured as the string specification.
The match string is then either a defined string or a syntax corresponding to "Character type
at pos.".
Identical formatting of the sent match string
The match string that is sent must be identical to the input made in adjustment support.
Permitted non-printable special characters must be sent as one character. A line break (\n)
for example as '\n' (ASCII value 0x0D) and not as '\''n' (ASCII values 0x2F and 0x6E).
Requirement for matching with 1D/2D codes
For 1D/2D codes all match options ("All", "Position", "ID", "GS1") are supported. The match
string that is sent must be formatted so that the information required for the comparison can
be extracted.
The following command must be sent to overwrite the match string:
Structure / description
Character no. 0 1
Meaning Command identifier
Value/ M A
character
● The characters 5 and 6 are interpreted as an unsigned 16-bit word and form the overall
length of the new match string starting at character 7.
● It is only possible to overwrite a match string if the reader is in processing mode and
matching was activated during program saving for the current program.
SIMATIC MV420 / SIMATIC MV440
Operating Instructions, 04/2013, A5E02371045-06
2 3 4 5
More significant byte
of the length m of the
following match
string
T C H 0x00-0xFF
Process interfacing via an automation system (PLC, PC)
10.6 Control via TCP/IP and RS-232
6
Less significant byte
of the length m of the
following match
string
0x00-0xFF
7 ... n-1 n
New match string with a
length m
All printable characters
303