Using the Command Interface
66
DP/AS-Interface Link 20E
Release 11/2002
C79000-G8976-C138–04
3.1 Command Interface of the DP/AS-Interface Link 20E
Note
A special function block (FC ASI_3422) is available for the AS-i commands in a
SIMATIC S7 DP master. This FC handles the command protocol described below
independently (see Section 3.2).
You will find FC ASI_3422 in the programming example on the diskette supplied
with the printed version of this manual.
Significance and Functionality
Via the command interface, you can control the response of the AS-i master
completely from within your user program.
AS-i commands are read and written using the acyclic services of PROFIBUS-DP
V1. In the user program on the DP master, you use the services read_record and
write_record (data record 2).
DP master
AS-i
slave 2
AS-i
slave 1
AS-i
slave n
AS-i slaves
PROFIBUS AS-Interface
DP/AS-i Link
write_record
S Command job
Acyclic services
SF
APF
CER
AUP
CM
6GK7 1415 2AA0
1
2
3
4
5
6
7
8
0
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
X 2
3 4
DIA
ADR
BF
DP-AS-Interface
Link 20
Send buffer
Receive buffer
for response
data or
error/status
information
read_record
S Command response
Data record 2
Status nibble
in the DP in-
put area
Status information
Figure 3-1
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