Logic Guide - OR (Built-in Functions, Function Blocks, and Conversions)

OR

Function Name	OR
Description	Outputs a True value when any of its inputs are True.
Arguments	Input 1 to Input n {ANY_BIT} For more information on the data types for the inputs and outputs, see Data Type Hierarchy.
Returns	Output {BOOL} If any of the inputs is True, the output is True. The output is only False if each of the inputs is False.

Function Name

Description

Outputs a True value when any of its inputs are True.

Arguments

Input 1 to Input n {ANY_BIT}

For more information on the data types for the inputs and outputs, see Data Type Hierarchy.

Returns

Output {BOOL}

If any of the inputs is True, the output is True. The output is only False if each of the inputs is False.

Example:

Function Block Diagram - OR:

An OR function has 2 inputs - Input 1 is from a flow sensor and is named 'FlowPresent' and Input 2 is from a Pump control and is named 'StopPump'. When the function receives a True input from either 'FlowPresent' or 'StopPump' it outputs a True value. The output is only False if all of its inputs are False.

ST Program - OR:

The OR function is used to provide a Boolean value that is True if any of its inputs are True. The syntax for an OR function in an ST Program is:

Output := OR (Input 1, Input n);

Where Output, Input 1 and Input n are defined as variables earlier in the ST program. Each input is separated by a comma and is a Boolean. The Output value is also a Boolean.