ifm
Device manual AS-i M4 Gateway Profibus DPV1 (AC1375, AC1376)
2012-02-23
Acyclic services for Profibus DPV1
Acyclic command in the DPV1 command channel
363
12.8.17
Acyclic command 35 (23hex) – write 7.4 parameter string of
an AS-i slave
5885
Request from fieldbus master to device
Bit
Offset
Word no.
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
1
UID
command request = 65
hex
2
res.
S
ST
SLA
command number = 35
dec
= 23
hex
3
parameter byte 1
parameter byte 0
4...16
parameter bytes 2...27
17
parameter byte 29
parameter byte 28
18
Field
number
DL
19
not used
not used
Legend:
UID
user ID
1 byte
00…FF
hex
= 0…255
dec
S
sequence bit
1 bit
a large data packet is transmitted in several partial sequences:
0 = data transmission completed
1 = data transmission not yet completed, at least one more packet follows
ST
slave type
1 bit
0 = single slave or A slave
1 = B slave (= addition of 20
hex
or 32
dec
to the slave address)
SLA
slave address
5 bits
00…1F
hex
= 0…31
dec
field number
1 byte
???
DL
data length
1 byte
number of bytes to be transferred
permitted values: 00…FF
hex
= 0…255
dec
(
data sheet of the slave)
NOTE
The number of the bytes to be sent must be divisible by 2 since the system always can transmit only
multiples of 2 bytes in the S7.4 protocol.
The control bytes defined in profile 7.4 with follow bit and valid bit are automatically added by the
system. Therefore, without segmentation, this command is limited to 20 bytes of parameter data. Larger
data volumes must be divided into several segments.
