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Technical Information
Where:
<STX> (Start of transmission) = 0x02
<ADDR> (Unit address) = when you select the RS232 communication, this field
is not handled and the controller always answers with its address stored in
EEPROM
<ADDR> (Unit address) = 0x80 + device number (0 to 31) (for RS485)
<WIN> (Window) = a string of 3 numeric 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 in the window
<DATA> = an alphanumeric ASCII string with the data to be written in the
window. In the case of a read command, this field is not present.
The field length varies according to the data type, as shown in
the following table:
Table 9
Data Type
Logic (L)
Numeric (N)
Alphanumeric (A)
<ETX> (End of transmission) = 0x03;
<CRC> = XOR of all characters following <STX> and including the <ETX>
terminator. The value is hexadecimal coded and represented by two ASCII
characters.
The SLAVE addressed responds with an ANSWER whose structure depends on the
MESSAGE type.
When the MESSAGE is a read command, the SLAVE responds transmitting a string
with the same structure as the MESSAGE.
Using the RS485 interface, the message structure is identical to that used
NOTE
for the RS232 interface, the only difference being the value assigned to the
ADDRESS <ADDR>.
Agilent 4UHV Ion Pump Controller User Manual
Field Length Max
Valid Characters
1
'0' = OFF
'1' = ON
6
'-', '.', '0' . . . '9' right justified with '0'
48
From blank to '_' (ASCII)
197
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