Agilent Technologies TwisTorr 305 FS User Manual page 208

Technical Information
<STX> (Start of transmission) = 0x02

<ADDR> (Unit address) = 0x80 (for RS 232)

<ADDR> (Unit address) = 0x80 + device number (0 to 31)

(for RS 485)
<WIN> (Window) = a string of 3 numeric character indicating the window

number (from '000' to '999'); for the meaning of each window see the relevant
paragraph.
<COM> (Command) = 0x30 to read the window, 0x31 to write into the window

<DATA> = an alphanumeric ASCII string with the data to be written into the

window. In case of a reading command this field is not present.
The field length is variable according to the data type as per the following table:
Table 21
Data Type
Logic (L)
Numeric (N)
Alphanumeric (A)
<ETX> (End of transmission) = 0x03

<CRC> = XOR of all characters subsequent to <STX> and including the <ETX>

terminator. The value is hexadecimal coded and indicated by two ASCII
character.
The addressed SLAVE will respond with an ANSWER whose structure depends
from the MESSAGE type. When the MESSAGE is a reading command, the SLAVE
will respond transmitting a string with the same structure of the MESSAGE.
Using the RS 485 interface, the message structure remains identical to the one
NOTE
used for the RS 232 interface, the only difference being that the value assigned to
the ADDRESS <ADDR>.
208
Field Length
1
6
10
Agilent TwisTorr 305 FS Remote Controller User Manual
Valid Characters
'0' = OFF
'1' = ON
'-', '.', '0' . . . '9' right justified with '0'
from blank to '_' (ASCII)