In last weeks’ post, I discussed acquiring data using a PLC to capture values from an analog card. I showed some fairly straightforward methods of capturing data using FIFO methods, averaging data values, and how some of the ladder logic …
Ladder Logic 402: Data Manipulation and Filtering Read more »
Todays post is in response to a request by Quy Phan, who I met a couple of weeks ago while teaching for Automation Training in San Diego. He is having some problems with some existing equipment concerning noise on his …
Last week I posted a fairly straightforward question at the end of my post on PLC Scanning. I then shared the post on Linked In as well as on my company’s Facebook page. One reason I share these posts on …
In my last post on PLC Memory Organization, I mentioned that I had not really covered how scanning actually works in a programmable controller. This is certainly a topic that needs to be discussed for an understanding of PLC programming, …
One of the first decisions that needs to be made when designing a PLC system is memory allocation and organization. In the early years of the PLC memory came at a premium… 1K (one kilobyte) of memory for the program …
Automation Direct has written a new post on the history of the PLC that you might find interesting. It can be found HERE and covers the early years of PLC development. It mostly discusses Dick Morley and the founding of …
Today’s post is in response to Dave Tompkins, who posted a request for help last week for an application. Since he posted it on one of my series posts on ladder logic (204: Auto Sequences) I decided to frame it …
When designing a control system, sometimes it becomes necessary or advantageous to communicate with devices that were not made by the PLC manufacturer. If these devices need to be placed on an Ethernet, DeviceNet or Profibus network there are methods …
Today’s topic involves a project I have been working on over the last few months. The project consists of adding process equipment including tanks, pumps, valves and instrumentation to an existing system… while it is running. Because production runs 24 …
Since I started this blog in early 2011 I have written a lot of articles on PLCs. The PLC is a major part of many industrial facilities and machines, and indeed has been an important part of my career. Now …
