Read Commands - Siemens SIMATIC MV440 Operating Instructions Manual

Process interfacing via an automation system (PLC, PC)
10.3 Control with FB 45 and Ident profile
10.3.3.4

READ commands

The following commands are supported:
MV command
● Trigger and read result string
● Read result string
● Read program number
● Read match string
Command: Trigger and read result string
To activate a trigger and read the result string, you will need to send a READ command
starting at address 0x0000. The following table shows the content of the command data area
specified in the command ("MOBY_CMD".DAT_DB_number or "instance DB-RFID standard
profile".RXREF) after fully processing the READ command (assuming that 0x0000 was
selected as the start address for the read).
The total length of the result string is stored at the (virtual) addresses 0x0000 and 0x0001.
● If the result string is longer than the number of characters to be read
("MOBY_CMD".length or "PIB_COMMAND".Length), the character string is truncated at
the back.
● If the result string is shorter than the number of characters to be read, the string is
padded with the value 0x00.
You can also configure the format text so that the result bits "READ", "MATCH", "N_OK" are
inserted in the string.
If you do not know of the total length of the result string, send a READ command starting at
address 0x0002 ("MOBY_CMD".address_MDS or "PIB_COMMAND".StartAddress = 2).
You can also start to read from any start address, for example when the result string is only
relevant starting at the 10th character in the code.
Table 10- 31 Moby_CMD
Command
260
Sub_
[hex] Command
[hex]
02 -
Length Address_
[dec] MDS [hex]
≥length 0
of the
result
string
DAT_DB_number DAT_DB_address
[dec]
Number of the Pointer to the start
data DB (for example
48)
FB45 stores the read result data here.
SIMATIC MV420 / SIMATIC MV440
Operating Instructions, 04/2013, A5E02371045-06
[dec]
word
(for example 0)