Command Chaining - Siemens SIMATIC Ident Function Manual

3.2.2

Command chaining

Command chaining permits various address areas of the transponder to be processed by
starting just one command. The advantage of command chaining is the optimum speed at
which commands can be processed on the communications module and on the reader.
A command chain is set up by the user by storing a succession of UDT 20s in a DB. The
chained commands must all be command type 4x. The last command in a chain must be
type 0x.
FB 45 uses this to detect the end of a command chain.
Example:
A transponder must process 4 data records. The command structure is stored in DB 47. The
transponder data is stored consecutively in DB 48.
Read
Read
Read
Write
Execution steps:
1. Define structure
Table 3- 14
Partial command
Partial command
Partial command
Partial command
2. Specify the "starting values" in the data view
FB 45 for MOBY U, MOBY D, RF200, RF300
Function Manual, 07/2012, J31069-D0166-U001-A4-7618
Transponder address
Transponder address
Transponder address
Transponder address
DB 47 - declaration view
STRUCT
ARRAY [1 ... 4]
UDT 20
END_STRUCT
0000 hex Length 600
1000 hex Length 100
1200 hex Length 1
1200 hex Length 1
Note:
1 ... 4 = No. of partial commands
Parameterizing
3.2 RFID commands
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