Compute and Math Instructions


The compute/math instructions evaluate arithmetic operations using an expression.

Available Instructions





If you want to:
Use this instruction:
evaluate an expression
add two values
subtract two values
multiply two values
divide two values
determine the remainder after one value is divided by another
calculate the square root of a value
take the opposite sign of a value
take the abosolute value of a value
ABS



You can mix data types, but loss of accuracy and rounding error might occur and the instruction takes more time to execute. Check the S:V bit to see whether the result was truncated.
The bold data types indicate optimal data types. An instruction executes faster and requires less memory if all the operands of the instruction use the same optimal data type, typically DINT or REAL.
A compute/math instruction executes once each time the instruction is scanned as long as the rung-condition-in is true. If you want the expression evaluated only once, use any one-shot instruction to trigger the instruction.


File name: PLC-15_IS-CMI.pdf
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