Agilent Technologies MS40+ - Page 89

Technical Information
RS 232/RS 485 Communication Description
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MS40+ Single Stage Rotary Vane Pumps User Manual / 87-901-008-01 (H.00) 89/104
T
ab. 7
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.
NOTE
Using the RS 485 interface, the message structure remains identical to the one
used for the RS 232 interface, the only difference being that the value assigned
to the ADDRESS <ADDR.
The controller can answers with the following response types:
Tab. 8
Type
Length
Value
Description
Logic
1 byte
-
after a read instruction of a logic window
Numeric 6 bytes -
after a read instruction of a numeric
window
Alphanumeric 10 bytes -
after a read instruction of an
alphanumeric window
ACK 1 byte (0x6) the command execution has been
successfully completed
NACK
1 byte
(0x15)
the command execution has been failed
Unknown
Window
1 byte (0x32) the specified window in the command is
not a valid window
Data Type Error 1 byte (0x33) the data type specified in the command
(Logic, Numeric or Alphanumeric) is not
accorded with the specified Window