greater than

Block Inputs: Two scalar inputs labeled “l” and “r.”

The greater than (>) block is useful in evaluating the Boolean > inequality. The output of the > block is 1 if and only if input “l” > input “r;” otherwise the output is 0.

If you right-click the > block, the Boolean block menu appears allowing you to assign a different function to the block.


1. Simple if-then-else construct

Consider a variable y such that:

If t > 2 then y = 7.2; else y = 0

Assume that t is simulation time. This system can be realized as shown below.

By multiplying a constant value of 7.2 with the output of the > block, y is guaranteed to assume a value of 0 until the inequality is true. When the inequality is true, y assumes a value equal to the output of the * block.

2. Modified if-then-else construct

Using the above equation, it can also be realized as:

The key difference in implementation is the use of a merge block rather than a * block. The merge block explicitly depicts the if-then-else structure, whereas the * block is a shortcut and can lead to confusion.