Table of Contents
Advertisement
<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:
Data Type
Logic (L)
Numeric (N)
Alphanumeric (A)
<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.
Some error settings are foreseen:
NOTE
PHD-4 Portable Helium Detector User Manual
RS 232 Communication Description
Field Length
Valid Characters
1
‘0’ = OFF
‘1’ = ON
6
‘-‘, ‘.’, ‘0’ . . . ‘9’ right justified with ‘0’
10
from blank to ‘_’ (ASCII)
/
87-900-120-01 (F )
Technical Information
125/140
5
Advertisement
Table of Contents
