Pepperl+Fuchs AS-I 3.0, Руководство пользователя

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AS-i 3.0 Command Interface
Structure of the Command Interface
2. Structure of the Command Interface
The command interface has the following structure shown in table 1 and table 2 .
Table 1
Bit T in the command interface is the toggle bit . The toggle bit is only necessary
in the case of interfaces which transfer the data cyclically.
The execution of a command of the command interface is declined, if the number
of the transferred parameters is too small, this could happen when the command
interface is too small or the tegram is too short.
Circuit selects the AS-i circuit. Circuit = 0 selects the first AS-i circuit.
Bit O is the list order bit. The commands for reading and writinig slave lists
support two different sorting schemas.
O = 0 selects the Standard schema.
O = 1 selects the Siemens schema (the sequence of the bits in the slave
lists bytes is inverse).
Parameter byte n is the n
th
parameter of the command. The number of
parameters is different for different commands. It is not necessary to set the
additional parameter bytes to 0 in the command interface, if a command
does not use the maximum number of parameter bytes (36)
Table 2
command request
byte
2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
1 command
2 T O circuit
3 request parameter byte 1
… …
36 request parameter byte 34
Tab. 2-1.
command response
byte
2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
1 command (mirrored)
2 T result
3 response byte 1
… …
36 response byte 34
Tab. 2-2.