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AS-i 3.0 Command Interface
Commands of the Command Interface
4.3.3.1
Structure of the response buffer
As the string to be transferred can be longer than the command interface, the
string is first saved in a buffer that can be read in sections using the buffer index
(i)
.
The first byte in the response buffer defines the current command. FF
16
signifies
transfer still active, FE
16
signifies transfer interrupted with errors. In the correct
case, the command from WRITE_ACYC_TRANS is given here.
The first sub-section of the string is read using i
≡
0, the second with i = m-2, etc.
The two following bytes (high, low) define the length of the response buffer.
It is recommended to start reading the data always using index i
≡
0. This mes-
sage also contains the header. The user data length is therefore reduced by 3
bytes.
Information!
Data with length i ½ 0 can be read successfull only once. Each further read command
with length i ½ 0 ist quit with an error. Therefore further read process (sections) must
be carried out with i >0!
Response buffer
Byte
2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
1
command
1
2
length byt
2
e n (high)
3
length byte n (low)
4
data 0
...
...
n+3
data n-1
Tab. 4-38.
1.
FFh signifies transfer still active, FEh signified transfer interrupted with errors. In the correct case the com-
mand from WRITE_ACYC_TRANS is given here.
2.
Transmit buffer length
n
.
Summary of Contents for AS-I 3.0
Page 1: ...AS I 3 0 COMMAND INTERFACE FACTORY AUTOMATION MANUAL...
Page 177: ......
