Delta Electronics DUP-B Series User Manual page 382

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CHRCHKSUM (Calculate Data Length of Texts or Characters and Checksum)
Equation
Var1 = CHRCHKSUM ("Var2", Var3, Var4)
Explanation
This command is used to calculate the data length of texts or characters and
checksum.
Var1 is the internal memory address that stores the text length of Var2.
Var2 is the string of text.
Var3 is the internal memory address that stores the checksum of Var2.
Var4 is the data length of the checksum that stores in Var3. 1 represents Byte and 2
represents Word.
Operation of checksum:
Convert format of each data characters to ASCII code and add them up. For example,
convert '2' to ASCII code '31H', convert '4' to ASCII code '34H' and the checksum is
31Hex + 34Hex = 65H.
Remark
Var1 and Var3 can be internal memory only. Var2 can be a string of texts only.
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Var4 can be constant only.
Example
Calculate the data length of "24" and checksum
$0 = CHRCHKSUM("24", $10, 2)
After the above operation, 4 is stored in $0 and 4 represents the data length is 2
WORDS. The checksum stored in $10 is 65H.
Revision May, 2010
Chapter 3 Creating and Editing Screens
3-361