Using The Acknowledgment And Command Counter - Siemens Simatic Ident Function Manual

Command / bit
TP
TPC
Job counter (CC_L)
Job counter (CC_H)
Acknowledgment coun-
ter (AC_L)
Acknowledgment coun-
ter (AC_H)
INITACT
Reserved
A.2.3

Using the acknowledgment and command counter

The cyclic control word is used for synchronization of frame exchange between DP
master/IO controller (the controller executing the block) and slave / I/O device (Ident device).
The transfer of non-cyclic command and acknowledgment frames via an MS1 or Record
Data CR connection can only be started when the start is indicated by the cyclic status word
of the Ident device in the acknowledgment counter.
The acknowledgment and command counter bits are used for synchronizing command
execution. The change to the command counter (executed by the Ident device) shows the
block that it can issue the next command. The change to the acknowledgment counter
shows that a command (within the Ident device) has been ended and the block can read out
the acknowledgment from the Ident device. The sequence of the change to the counters
(executed by the Ident device and monitored by the block) is the same for both counters
(acknowledgment and command counter) and is represented in the figure below.
Ident profile and Ident blocks, standard function for Ident systems
Function Manual, 10/2018, C79000-G8976-C387-04
Significance for RFID systems
Transponder Presence
1 = There is a transponder in the
antenna field of the reader.
Transponder Presence Changed
(only when Presence_Mode is ac-
tive)
1 = A new transponder enters the
antenna field of the reader or a tran-
sponder has left the antenna field.
The parameter is set to "FALSE"
after the successful execution of the
next "INVENTORY" (0x80, 0x81,
0x87) or "INIT" command.
Less significant bit of the command counter
More significant bit of the command counter
Less significant bit of the acknowledgment counter
More significant bit of the acknowledgment counter
1= Indicates that the reader/optical reader is currently executing a start
procedure. After the bit is reset to "0", it is expected that a "Write-Config"
command sent by the block is received.
Commands other than "Write-Config" are rejected with an error. The bit is
intended to be used in the resynchronization of the acknowledgment and
command counter.
Reserved bits
A.2 Cyclic data
Significance for optical readers
Manufacturer-specific
Not used
Appendix
137