4
DESCRIPTION
ENGLISH
STANDARD Communication Protocol
WARNING!
In an instruments network, the $00 code can be used only for sending write
commands. An interrogation would generate a simultaneous response from
all of the instruments, with the possibility of malfunctions.
3.3 Data Request Sequence
By the master, a data request sequence is sent to the instrument (slave) to read information on
the device (measured values, programmed parameters,...). This interrogation cannot change
instrument confi guration. The following description shows the correct sequence of characters for
a proper interrogation:
<STX>02R63<ETX>($51)
[begin block character]
[instrument identifi cation]
[command]
[end block character]
[check character]
[begin block character]
It is always <STX> ($02) character.
[instrument identifi cation]
It is usually represented by the Logical Number ($01...$FF). The character S ($53) can also be
used followed by the instrument Serial Number (9 alphanumeric characters).
[command]
It is always R ($52) character followed by the variable number to be read (see section 4.1), ex-
pressed in hexadecimal.
[end block character]
It is always <ETX> ($03) character.
[check character]
It is a single character which results from EXCLUSIVE OR (XOR) of all the characters from <STX>
up to and including <ETX>. It is used to check the transmitted data.
