GE PACSystems RX7i Cpu Programmer's Reference Manual

Also see for PACSystems RSTi-EP: Reference manual User manual

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GE PACSystems RX7i Cpu Programmer's Reference Manual Manual pdf 299 page image

Chapter 6. Service Request Function284 PACSystems* RX7i, RX3i and RSTi-EP CPU Programmer's Reference Manual GFK-2950C6.7 SVC_REQ 6: Change/Read Number of Words to ChecksumUse SVC_REQ 6 to read the current word count in the program to be check-summed or set a newword count. By default, 16 words are checked. The function is successful unless some number otherthan 0 or 1 is entered as the requested operation.The parameter block has a length of 2 words.6.7.1 To read the word count:Enter a zero in the first word of the parameter block.Address 0Address +1IgnoredThe function returns the current checksum (word count) in the second word of the parameter block.No range is specified for the read function; the value returned is the number of words currently beingcheck-summed.Address 0Address +1Current word count6.7.2 To set a new word count:Enter a one in the first word of the parameter block and the new word count in the second word.Address 1Address +1New word countThe CPU changes the number of words to be check-summed to the value given in the second word ofthe parameter block, rounded up to the next multiple of 8. To disable check-summing, set the newword count to 0.