Agilent Technologies 969-6500, Руководство пользователя, Страница: 284 / 306

18
Technical Information
Procedure to Connect the Serial and I/O ports
to an External Cable
284/306 Turbo-V 903 Pumping System User Manual / 87-901-016-01 (A)
<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 4
Data type Field length Valid characters
Logic (L) 1 ‘0’ = off
‘1’ = on
Numeric (N) 6 ‘-‘, ‘.’, ‘0’ . . . ‘9’ right
justified with ‘0’
Alphanumeric (A) 10 from blank to ‘_’ (ASCII)
<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
.