Topic: DMD0130

TRUNC - Truncate Real to Whole Number

This instruction can only be used in the Expression parameter of the Calculate Expression (MATH) instruction.

The Truncate Real to Whole Number (TRUNC) instruction will return only the whole number portion of a Real number, that is, the portion of the number to the left of the decimal point. The number will NOT be rounded. Negative real numbers return negative values. This math function returns an integer value.

The expression parameter consists of all the text between the bounding parentheses. Any expression parameter can be a constant value, a bit or numeric memory location, an arithmetic expression, and/or mathematical function or other expressions up to a maximum of 1024 characters. Expressions can be nested, so use of parentheses is recommended to ensure proper evaluation order.

In the example to the right

• If R0 = 3.14159 the value in D0 would be 3
   

• If R0 = -3.14159 the value in D0 would be -3

See Also:

• FRAC - Fractional Portion of a Real Number
   

• ROUND - Round Real to Nearest Whole Number
   

• TRUNC - Truncate Real to Whole Number

Related Topics:

• MATH - Calculate Expression

Rung Example: