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

Страница: 73 / 160

Using the Command Interface
73
DP/AS-Interface Link 20E
Release 11/2002
C79000-G8976-C138–04
Table 3-4 Formal Parameters, continued
Name Remarks Memory Area Data Type Para Type
RECV I ANY I,Q,M,D,L Receive buffer
This buffer is only relevant for
commands that supply response data.
The parameter references a memory
area in which the command response
is stored. The length information in the
ANY pointer specified here is
irrelevant. The FC itself obtains the
length of the response data.
for example: P#DB30.DBX 20.0 byte 1
DONE Q BOOL Q,M,D,L DONE = 1 signals ’job completed
without error’.
ERROR Q BOOL Q,M,D,L ERROR = 1 signals ’job terminated
with error’.
STATUS I/Q DWORD M,D 1st word: Job status / error code (see
Table 3-5);
For ’job terminated with error’, an error
code is generated that describes the
error in greater detail.
2nd word: Required by the FC for
internal purposes and must not be
modified.
Note:
For FC calls to different
DP/AS-i Link 20E modules, different
double words must be used for the
STATUS parameter.
Commands in the User Program
To work with commands, you require the following in your user program:
1. In the warm restart branch of your S7 user program, call FC ASI_3422 once
with the parameter value STARTUP = TRUE.
2. Specify the command call in a send buffer in the user program. You transfer this
send buffer with the SEND call parameter.
3. Depending on the command type you will also require a response buffer. You
transfer this response buffer with the RECV call parameter. For status
information, the response buffer is not required for this FC interface.
4. Activate the job with the parameter ACT=1
5. You then query the parameters DONE, ERROR and STATUS. For handling
these parameters in the user program, note the signal sequence of the
parameters explained below.
The diskette supplied with this manual contains sample programs.