Explain MAX instruction using example.

 Explain MAX instruction using example.

Application: -Understand the concept of MAX instruction in the PLC. Write the PLC program using ladder diagram language to understand the concept.

Diagram: -

Explanation:-

Here we will understand the concept using an example. MAX instruction is used to define MAX value out of two values. So this instruction will compare two value and update the result in the output register.

For example assume we want to show MAX value out of two values. So we can take two values entry (MW10 and MW12 register for two value entry) in the HMI and one output field for output (the result will be updated in the MW14 register). In this entry field, we will enter two values here 50 and 60 so the output result will be 60.

PLC program:-

Write the ladder program for MIN instruction using ladder diagram language. Here for ladder logic, we can use any supported PLC system like S7-1200, S7-1500, or any other PLC which can support this instruction. In our application, we have used S7-1200 PLC for reference.

M Memory:-

IN 1:-MW40

IN 2:-MW42

OUT:-MW44

Network 1:- MAX instruction operation

 

PLC program Explanation:-

In network 1, we have taken MAX instruction. Here we are entering 50 in the MW 50 and 60 in the MW42 so the result will be updated in the MW 44 register. And it will be 60