Read_Mv - Siemens SIMATIC Ident Function Manual

4.5.2.3

Read_MV

The "Read_MV" instruction reads the read result of an optical reader. The "Read" instruction
must be used to read the configuration. The length of the data to be read is calculated
automatically by the instruction based on the length of the created receive buffer. The actual
length of the read result is output in the "LEN_DATA" output parameter. The data will be
saved in the "IDENT_DATA" data buffer. If the buffer is too small, the error message
"0xE7FE0400" appears and the expected length is output at "LEN_DATA".
To achieve an optimum speed, we recommend that you adapt the length of the data type
"IDENT_DATA" so that this is as close as possible to the maximum expected length of the
read result (2 bytes code length + read code).
Figure 4-6
Table 4- 6
Parameter
IDENT_DATA
LEN_DATA
Ident profile, Add-on instruction for Rockwell systems
Function Manual, 01/2019, C79000-G8976-C410-03
Instruction "Read_MV"
Explanation for the instruction "Read_MV"
Data type
SINT[10]
INT
4.5 Programming add-on instructions
Default values Description
0 Read result
The length of the read code is located
in bytes 0 and 1.
Note:
When necessary, an array of any size
can be transferred to this parameter.
Note that the array must be ≥ 10 bytes
long (e.g. "SINT[12400]").
0x00 Length of the read result ≙ 2 bytes
code length + read code
Configuring the instructions
25