COMMUNICATION PROTOCOL IN MODE SINGLE AND MULTI
RRF installation and operating manual
Pag. 13
Where:
<FLAGS>
: Register of flags, encoded as shown in the table below:
The communication parameters are fixed to
38400,N,8,1
. The transmission strings are as follows:
Binary Encoding:
0x80
<TRF1>
<TRF2>
. . .
<TRFn>
<CS>
EOT
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
0
Timeout
1
Out of range Overweight Underweight Unstable weight
Negative sign
<HW>
: Most significant byte (bit 23 … bit 16) of the weight value in 24-bit (0xFF if timeout)
<MW>
: Intermediate Byte (bit 15 … bit 8) of the weight value in 24-bit (0xFF if timeout)
<LW>
: Least significant byte (bit 7 … bit 0) of the weight value in 24-bit (0xFF if timeout)
<VBAT>
: Battery voltage in tenths of Volts (binary data)(0xFF if timeout)
<CS>:
Checksum calculated as the sum of the first 6 bytes in binary 2's complement (0xFF - sum)
EOT
: end of transmission; character of end string (ASCII value0x04).
<PESO>:
ASCII string of weight expressed with 8 characters right justified, with any decimal point
and minus sign. (In case of timeout are transmitted 8 characters „-‟).
<BATT>
: ASCII string of voltage battery, 2 characters expressed in tenths of Volts.
ETX
: end of text; text end character (ASCII value 0x03).
<CHKSUM>
: two-character checksum of string data. It is calculated by performing the exclusive OR
(XOR) of all the characters from STX to ETX, STX and ETX excluded. The result of the XOR is de-
composed into two separate characters, considering separately the upper 4 bits (first character) and
the lower 4 bits (second character
).
The two obtained characters are then encoded ASCII. (Example:
XOR = 5Dh; C C = «5D» that is 35h e 44h).
EOT
: end of transmission; character of end string (ASCII value 0x04).
ASCII Encoding:
0x80
<TRF1>
<TRF2>
<TRFn>
ETX
<CHKSUM>
EOT
. . .
Where:
<STATO>
: weight status, can take the values shown in the following table:
“S”
“M”
“E”
“O”
“U”
“Z”
“T”
Stable weight Weight in motion Out of range Overweight
Underweight
Initial zero not performed
Timeout
String for weight request:
In case of transmission on request, for both encoding type, The request string is as follows:
0x80
“N”
EOT
Where:
“N”:
character identifier of the request (ASCII value 0x4E).
EOT
: end of transmission; character of end string
(ASCII value 0x04).
<STATO>
<PESO>
<BATT>
Where <TRFx> consists of 3 fields:
<FLAGS>
<HW>
<MW>
<LW>
<VBAT>
Where <TRFx> consists of 5 fields:
