Topic: DMD0130

TRUNC - Truncate Real to Whole Number

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.

Note: Use the F9 key or click the 'three dot box' at the right edge of the parameter field to open the Default Element Selection Tool (the Element Picker or the Element Browser) or use the Down-Arrow key (Auto-Complete) on any parameter field to see a complete list of the memory locations that are valid for that parameter of the instruction.

Result specifies a location to store the result of the calculation. This can be any writable numeric location.

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 above:

• 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: