17 Technical Information
RS 232/RS 485 Communication Description
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TwisTorr Medium-TMP Rack Controller User Manual /
87-901-049-01 (B)
<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. 19
Data Type
Field Length
Valid
Characters
Logic (L)
1
‘0’ = OFF
‘1’ = ON
Numeric (N)
6
‘-‘, ‘.’, ‘0’ . . . ‘9’ right
justified with ‘0’
Alphanumeric (A)
Up to 14
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>.
