Command Repetition - Siemens Simatic Ident Function Manual

If several commands are executed in the chain for which data is returned, the position of the
data in the receive buffer "RXREF" can be set for each individual command using the
"IID_CMD_STRUCT[x].OFFSETBUFFER" parameter.
Note
"IID_CMD_STRUCT[1]" reserved for "INIT"
In the Ident profile, the "IID_CMD_STRUCT[1]" parameter is normally reserved for "INIT". If
you want to use "IID_CMD_STRUCT[1]" for another command, make sure that the reset
parameters are written into this parameter when there is an "INIT".
3.5.4.8

Command repetition

The Ident profile supports command repetition (Repeat command).
Note
Command repetition is device-specific
Please check whether the Ident device you are using supports command repetition.
At the time of publication of this manual, command repetition is supported only by the
RF61xR/RF68xR readers (as of V3.0) and the ASM 456 (as of V5.0) and RF18xC
communications modules.
How it works
After restart (or "INIT") of the reader, the Ident profile transfers the command or command
chain once to the reader. Transmission of the command is automatic with the first
"EXECUTE". This command (or the last command or the command chain) always remains
buffered on the reader. If command repetition is started, the temporarily stored command on
the reader is executed again, and the result(s) transferred to the Ident profile.
Make sure that the "EPC-ID/UID" of the commands to be repeated has the value 0. If the
EPC-ID as a different value, an error message is generated.
Effects of command repetition
● The data transfer on PROFIBUS/PROFINET is minimized. This reduction has a positive
effect particularly with extensive bus configurations and slow transmission speeds.
● The reader processes each transponder regardless of the Ident profile. This has a
particularly advantageous effect on gate applications since all transponders are always
identified with the full reader scan speed.
● Total data throughput is increased considerably particularly with controllers that have few
system resources for acyclic frames.
Ident profile and Ident blocks, standard function for Ident systems
Function Manual, 10/2018, C79000-G8976-C387-04
Setting parameters for blocks
3.5 Programming the Ident profile
107