How Ladder Logic Program Scan Works

How Ladder Logic Program Scan Works

PLC programs scan cyclically. This means that it is repeated many times and in the same order. The primary sequence of a PLC scan is reading the inputs, executing the program, diagnostics, and communication, and updating the outputs. We will look at these scan items with particular attention to how the ladder logic program is … Read more

Learn PLC Programming Free Now – Video

Learn PLC Programming Free Now

We can learn plc free by using the Do-More Designer simulator. This is free, fully functional programming and simulator software. The PLC simulator also allows communication through the Ethernet and Serial ports of the computer to help you learn about HMI and communication. This video series will take you through the simulator’s basics of installing, … Read more

Productivity 2000 PLC Ladder Logic Counter

Productivity 2000 PLC Ladder Logic Counter

Most programmable logic controller (PLC) programs will include a counter instruction. The Productivity 2000 Series PLC has two different counter instructions for your program. These can be used in several different ways to adapt to your application. Basically, counters are used to count up or down to a specific limit. When the limit is reached, … Read more

Timing Diagram NOT Just Used for a Timer

Logic circuits in a PLC ladder logic program are either on or off. The inputs change, which will affect the outputs. This can be expressed in a timing diagram. The timing diagram or chart will show you how the ladder logic program will respond to the changing states of the inputs and outputs. This visual … Read more

Ladder Logic (NO) Contact – 3 Things to Know

Ladder Logic Normally Open (NO) Contact - 3 Things to Know

Normally open (NO) contacts or inputs in the PLC ladder logic program do not mean the same as a wired normally open switch. NO contacts on the ladder logic provide the logic condition for the rung to turn on the output. We will be looking at three things about the normally open (NO) contact on … Read more

Productivity 2000 Series PLC Online Programming

The Productivity Suite Software allows us to modify our existing program and execute the new code without stopping the scanning of the PLC. This is referred to as online programming or editing. We change the ladder logic code and when we save it to the PLC, the current scan of the PLC is held until … Read more