AW Gear Meters EMO-500 - Manual (Page 34)

EMO-500
Operation and Programming Manual
33
>01J03340F3587XXcr
^.....................start of string must use the > sign
^^..................unit number
^..................write command J (use K to read)
^^^^...........address to write into
^^...........byte written to 0334
^^.........byte written to 0335
^^.......byte written to 0336
^^.....checksum
.....carriage return
If the operation was successful, the EMO-500 answers with: Acr.
The following error messages have been implemented in the EMO-500 protocol:

NO1cr - Undefined command (something other than K/J)

NO2cr - Checksum error

NO3cr - Non printable ASCII character
OPTO 22 has published a booklet on the protocol format.
Checksum Calculation
The calculation for the string variables in the read command would be as follows:
>01K0F3404XXcr
^^^^^^^^^.......these characters are used in the calculation.
Add the values for the ASCII Decimal variables.
HEX 0 + 1 + K + 0 + F + 3 + 4 + 0 + 4
ASCII 48 + 49 + 75 + 48 + 70 + 51 + 52 + 48 + 52 = 493
To calculate the final checksum, convert the decimal number 493 into HEX (493=1EDh) and take the last
two characters (ED) for the checksum. The final string would look like this:
>01K0F3404Edcr