Agilent Technologies TV 551 Navigator, User Manual

Page: 288 / 328

17 Technical Information
How to Connect the Open-Collector Inputs of the Controller
288/328 TV 551/701 Navigator User Manual / 87-900-934-01 (P)

<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:
Tab. 6
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: