Siemens SIMATIC MV440 - Page 252

Process interfacing via an automation system (PLC, PC)
10.3 Control with FB 45 and Ident profile
SIMATIC MV420 / SIMATIC MV440
250 Operating Instructions, 04/2013, A5E02371045-06
Command: Read program number
The "Read program number" command is used to prepare reading of the current program
number.
The MV command itself does not perform the actual read. For this reason, the data of the
WRITE command contains only the MV command itself.
The user sends the MV command "Read program number" with the WRITE command and
waits for a positive response. A READ command is then used to read out the actual program
number, see also READ commands (Page 260).
The WRITE comman
d must specify a length of 0x1 ("MOBY_CMD".length or
"PIB_COMMAND".Length = 0x1), otherwise a negative response will be sent.
Table 10- 10 Moby_CMD
Command
[hex]
Sub_
Command
[hex]
Length
[dec]
Address_
MDS [hex]
DAT_DB_number
[dec]
DAT_DB_address
[dec]
Number of the
data DB (for example
48)
Pointer to the start
word
(for example 0)
01 - 1 0
Pointer to the user data to be sent to the
reader.
Table 10- 11 PIB_COMMAND
Parameter Value
CMD 0x71
OffsetBuffer 0x00
UID 0x00
Length 0x01
StartAddress 0x00
Table 10- 12 Command data area (FB45: Data DB, RFID standard profile: TXBUF or RXBUF)
Address Value Meaning
0x0000 0x02 "Read program number"
command identifier