85
ifm
Device Manual Supplement: Acyclic data records and Command interface (AC14 and AC4S)
2017 / 09
Command channels
>
4.3.17
Command 0x0023 – Write parameter string of an AS-i slave (S-7.4)
8831
>
Command request channel (fieldbus master >>> device)
11145
Offset
Word no.
Bit
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
1
UID
2
command number
3
Number of bytes to be transmitted
reserved
ST
SLA
4...m
parameter byte n+1
parameter byte n
(m+1)...120
The area is completely ignored.
It does not matter whether the data area exists or what data is contained.
Legend:
SLA
slave address
5 bits
0x00…0x1F = 0…31
ST
slave type
1 bit
0 = single slave or A slave
1 = B slave (= addition of 0x1F to the slave address)
UID
user ID
1 word
0x0000…0xFFFF = 0…65535
The user ID ensures clear identification of the commmand response data
of the command request data sent before. The user can assign any user
ID in the command request. The AS-i master reflects the user ID from the
command request into the corresponding command response.
The number of the bytes to be sent must be divisible by 2 since the system always transmits
only multiples of 2 bytes in the S7.4 protocol.
