R&S NRP2, Руководство пользователя

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Remote Control Fundamentals
R&S
®
NRP2
180 User Manual 1173.9157.02 ─ 03
The ASCII character # denotes the beginning of the data block. The next numeral speci-
fies the number of subsequent digits defining the length of the data block. In the example
above, the four digits specify a length of 9600 bytes. The data bytes follow next. During
transmission of these data bytes, all terminators and other control data are ignored.
Coupled commands
Setting one command influences the value of another command. According to SCPI
1999, this should be avoided but it makes sense when user-friendly high-level measure-
ment commands are to be provided to configure an entire section of the device at once.
The high-level commands
CONFigure
,
FETCh
,
READ
and
MEASure
are therefore an
exception to this rule.
5.8 Device Model and Command Processing
The device model shown in
​
figure 5-2 was prepared from the point of view of the pro-
cessing of remote control commands. The individual components operate independently
of each other and simultaneously. They communicate with each other by means of mes-
sages.
Fig. 5-2: Device model for remote control
5.8.1 Input Unit
The input unit receives the commands in the form of characters from the remote control
interface and collects them in the input buffer. The input unit sends a message to the
command identification as soon as the input buffer is full or as soon as it receives a
delimiter. The received data is processed in the parser (command identification).
5.8.2 Command Identification (Parser)
The parser analyzes the data received from the input unit. Data is processed in the
sequence in which it was received. Syntax errors in the command are recognized and
passed on to the status reporting system. Following the syntax test, the value range of
the data is verified and the setting is adapted. Only after the command has been com-
pletely executed will the next command be processed.
Device Model and Command Processing