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The value for the Referenced FB parameter references the block number of an already-programmed analog
math function block.
Description of the function
The analog math error detection block sets the output when the referenced analog math function block has
an error. You can program the function to set the output on a zero division error, an overflow error, or when
either type of error occurs.
If you select the automatically reset checkbox, the output is reset prior to the next execution of the function
block. If not, the output retains its state until the analog math error detection block is reset with the R
parameter.
In any scan cycle, if the referenced analog math function block executes before the analog math error
detection function block, the error is detected in the same scan cycle. if the referenced analog math function
block executes after the analog math error detection function block, the error is detected in the next scan
cycle.
Analog math error detection logic table
In the table below, Error to Detect represents the parameter of the analog math error detection instruction
that selects which type of error to detect. Zero represents the zero division bit set by the analog math
instruction at the end of its execution: 1 if the error occurred, 0 if not. OF represents the overflow bit set by
the analog math instruction: 1 if the error occurred, 0 if not. Zero division OR Overflow represents the logical
OR of the zero division bit and the overflow bit of the referenced analog math instruction. Output (Q)
represents the output of the analog math error detection function. An “x” indicates that the bit can be either
0 or 1 with no influence on the output.
Error to
Detect zero of Output
Zero
division 1 X 1
Zero
division 0 X 0
Overflow X 1 1