Kistler-Morse KM ultrawave - Manual (Page 83)

checKsuM cAlculAtion
The one-byte checksum is calculated by adding the Hex values of all ASCII characters between the start of
message character ‘>’ or acknowledge character ‘A’ and the checksum character ’ss.’ Overflows from the
addition are ignored.
example:
Request
To request engineering units from a UltraWave Series controller, the command is:
>aa2ssr
If the controller address is ‘3’, the command is:
>032ssr
Calculating the checksum ‘ss’ as the sum of the Hex values of all characters between ‘>’ and ’ss’:
032 ASCII = 30 Hex + 33 Hex + 32 hex = 95 Hex
‘0’ ‘3’ ‘2’
Therefore, the ASCII string transmitted to the controller is:
> 0 3 2 9 5 CR
3E 30 33 32 39 35 0D Hex
Response
The response to a request for engineering units is:
Adddddddssr
If the level is 63.84 feet (transmitted without decimal points as 6384) and there is no echo loss, the
response is:
A0006384ssr
Calculating the checksum ‘ss’ as the sum of the Hex values of all characters between ‘A’ and ‘ss’:
0006384 ASCII = 30 Hex+ 30 Hex+ 30 Hex+ 36 Hex+ 33 Hex+ 38 Hex+ 34 Hex = 165 Hex
‘0’ ‘0’ ‘0’ ‘6’ ‘3’ ‘8’ ‘4’
Ignoring the overflow, the checksum is 65 Hex. Therefore, the ASCII string transmitted back to the
master is:
A 0 0 0 6 3 8 4 6 5 CR
41 30 30 30 36 33 38 34 36 35 0D Hex
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97-1163-01 Rev. D
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