Example Of A Command String; Time Sequence Of Processing - HBM WE2108 Serie Referenzhandbuch

Scale electronic unit (NSW)
2.3
2.3.1
The commands are processed by the WE2108 in a fixed time cycle. To be able to store char-
acters from the control computer at any time, a reception buffer for approx. 60 characters
exists. Therefore as a rule, several commands can be sent one after the other without wait-
ing for the answer.
There is also a buffer for the output of the answers. This compensates for differences in the
speed of processing and character output.
In the broadcast mode (setting S98, no output of answers) the answer of the last executed
command is stored (see Section 8.2.2 ).
The following rules apply for processing:
•
•
•
WE2108

Example of a command string

Command
ASF?;
ASF3;
ASF?;
BSF?;
;

Time sequence of processing

In the normal case the commands are executed in the order of reception. While a com-
mand is being processed, further commands which are then filed in the input buffer can
already be received.
The Select command (Sxx, see Page 117) is executed immediately after reception, even if
earlier commands are in the buffer but have not yet been executed. If the unit is just
sending an answer, this is immediately stopped by the Select command (with a new
address). In this way the bus line is immediately free in a configuration with several units
(RS−485 interface). On the other hand, already started answers are not output com-
pletely. Therefore a communication program must ensure that a required answer was
received before it outputs a new Sxx command.
The command BDR switches the baud rate over and answers with the new baud rate.
Further commands which were received before execution of the BDR command and are
still in the input buffer are deleted.
Answer
7CRLF
0CRLF
3CRLF
?CRLF
?CRLF
Explanation
Query
Answer
Command: set parameter
Confirmation of execution
Query
Answer
Faulty entry
Answer to error
"Blank command"
Answer to error
73
HBM