Siemens DP/AS-Interface Link 20E, Руководство пользователя

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Using the Command Interface
68
DP/AS-Interface Link 20E
Release 11/2002
C79000-G8976-C138–04
Evaluate status nibble
Further evaluation of status
nibble necessary
Command processing active
Command processing completed
Completed without error
and without response data
or
terminated with error Completed without error and
with response data
Read_record:
2–byte return value
Terminated with error
Completed without error
and without response data
Read_record:
n bytes of response data
New command call (write_record) possible
Figure 3-2
Table 3-1 Coding of the Status Nibble
Status nibble (1st byte of
the digital input data)
Meaning
Bit 7 Bit 6 Bit 5 Bit 4
1 0 0 0 Startup ID 1:
Following a startup/restart of the AS-i master, the status nibble changes
between the values 1000
B
and 1110
B
.
It is possible to trigger a command with the user program
1 1 1 0 Startup ID 2:
Following a startup/restart of the AS-i master, the status nibble changes
between the values 1000
B
and 1110
B
.
It is possible to trigger a command with the user program
1 1 0 0 Reserved for SIMATIC S7 application FC “ASI_3422”
It is possible to trigger a command with the user program
0 0 1 0 Command processing active
It is not possible to trigger a command with the user program