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Technical Information
RS 232/RS 485 Communication Description
When a data is indicated between two quotes ('...') it means that the indicated
NOTE
data is the corresponding ASCII character.
Tab. 5
DATA TYPE
Logic (L)
Numeric (N)
Alphanumeric (A)
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.
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<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:
FIELD LENGTH
1
6
10
<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.
VALID CHARACTERS
'0' = off
'1' = on
'-', '.', '0' . . . '9' right
justified with '0'
from blank to '_' (ASCII)
TV 801 Navigator User Manual / 87-900-953-01
(G)
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