Introduction to Cascading Counters By cascading counters, you can virtually have a limitless number of counts using CTU instructions. With the older 16 bit processors, the maximum count was 32767 before the counter overflowed. Using 32 bit processors, however, this maximum count for a signed DINT is 2147483647 before it Read More »
Introduction to Troubleshooting with Add-On Instructions Today, we’ll look at a method for troubleshooting with Add-On Instructions. Add-On instructions make life easier for both the programmer, and the troubleshooter. However, it’s important to understand how add-on instructions work, and why we need them. In the older processors, the programmer wrote Read More »
Introduction to Saving Energy in ControlLogix We all like to save money, and there are always a few tweaks you can do to your project for saving energy in ControlLogix. One of the simplest examples is lighting. When a light has been left on, shut it off after a certain Read More »
Introduction to the ControlLogix One Shot (ONS) The ControlLogix One Shot instruction triggers an event. Although this is a very simple concept, it’s difficult for many to grasp. It’s very difficult for some people to understand what cannot be seen! The one shot instruction allows outputs after it to go Read More »
Introduction to the Hour Meter on ControlLogix The advantage of having an hour meter on ControlLogix is for routine maintenance. With this purpose in mind, we use a retentive timer in conjunction with a counter. The counter will keep track of total machine run hours. Likewise, with an hour meter, Read More »
Why Calculate Sunrise and Sunset in a PLC? In the olden days, you used a photo resistor to detect when the sun has risen or set. The problem with this are obvious. You are adding an extra component that will degrade over time. Not to mention the fact that cloudy Read More »
Introduction to ControlLogix Three-Way Switching Standard three-way switches are wired to control a light from two different locations. In this post, we will write a simple program to control lights from many locations. We will also set up the ControlLogix three-way switching to end up in the correct position. In Read More »
Introduction to PLC-5 Block Transfers One of the most difficult concepts for most people to grasp is the PLC-5 Block Transfers. Think of Block Transfers as simply a copy instruction. You are copying data from a module to somewhere else in the memory of the processor. The Block Transfer Read Read More »
Introduction to Sump Level Logic When writing sump level logic, keep in mind, we need to know what the sump level is. We usually provide that to the processor with an analog input. We’ll assume that you have the level transmitter set up, we will scale this transmitter into inches. Read More »
