Kistler-Morse KM SVS2000 User Manual
Page 75
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www.kistlermorse.com
97-1129-01 Rev. D
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 gross engineering units (such as weight) from a SvS 2000, the command is:
>aaWssr
If the SvS 2000’s address is ‘3’, the command is:
>03Wssr
Calculating the checksum ‘ss’ as the sum of the Hex values of all characters between ‘>’ and ’ss’:
03W ASCII = 30 Hex + 33 Hex + 57 hex = BA Hex
‘0’
‘3’
‘W’
Therefore, the ASCII string transmitted to the SvS 2000 is:
>
0
3
W
B
A
Cr
3E
30
33
57
42
41
0D
Hex
RESPOnSE
The response to a request for gross engineering units is:
A±dddddddssr
If the weight is +6384, the response is:
A+0006384ssr
Calculating the checksum ‘ss’ as the sum of the Hex values of all characters between ‘A’ and ‘ss’:
+0006384 ASCII = 2B Hex+30 Hex+30 Hex+30 Hex+36 Hex+33 Hex+38 Hex+34 Hex = 190 Hex
‘+’ ‘0’ ‘0’ ‘0’ ‘6’ ‘3’ ‘8’
‘4’
Ignoring the overflow, the checksum is 90 Hex. Therefore, the ASCII string transmitted back to the master is:
A
+
0
0
0
6
3
8
4
9
0
CR
41
2B
30
30
30
36
33
38
34
39
30
0D Hex