Simple Ladder Pulse
This morning I had someone send a ladder diagram on a dry-erase board with an attempt at creating a 10 second pulse to dispense something. It was much more complex than it needed to be and I tried to explain …
Tag: ladder logic
Ladder Logic 309: Allen-Bradley DDE/OPC Link to Excel
It’s been a while since I’ve added to the Ladder Logic series, so this post serves several purposes. It serves as the 7th video in the ControlLogix Odyssey series, it will be posted on YouTube as an ad, and it …
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The Case for Ladder Logic
Lately I have seen a lot of posts promoting Structured Text on forums and Linked In. Structured Text is one of the 5 (or 6) standard PLC languages described in IEC 61131-3. While I have used ST in the past …
Application 001: Man Crossing
As many of you know, I have been pretty focused on my Automation Academy project. Because of this and some guidance I received this Summer to “repurpose everything”, I have decided to start an applications series here on the Primer. …
Ladder Logic 404: VFD Encoder Control/Siemens
Today’s post doubles as a Ladder Logic series post and an introduction to the last videos in the Siemens Step 7 Odyssey series on my YouTube channel. Last week I covered a bit about how a Variable Frequency Drive interfaces …
Ladder Logic 309: Allen-Bradley Produced-Consumed Tags (Video)
Today’s post is a continuation on Jason Lafever’s questions on PLC to PLC communications. PLCs often have a need to send messages to each other, and all have some method of directly sending a message to read or write tags …
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Ladder Logic 308: Allen-Bradley’s MSG (Message) Instruction – Video
Today’s video is in response to a post I put on my Facebook automation forum, Automation Training. Jason Lafever asked if I would cover a bit on Allen-Bradley’s MSG (Message) Instruction, and cover Produced-Consumed Tags. I decided to split these …
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Ladder Logic 307: Data Average and Archive
Today’s post is in response to Yusuf Shaikh, who asked a question in a Facebook forum on PLCs. He asked “How to calculate average of drive current tag for every 15 seconds in Micrologix 1400 PLC?“ Of course there are …
Ladder Logic 306a: Simulation
Today’s post relates to a new method I am using to teach some of my advanced classes. In a basic PLC training class, pushbuttons and pilot lights built into a trainer are used to complete exercises, usually in order to …
Ladder Logic 403: Message Scrolling and Multiple Faults
Today’s post is in answer to a question from Bruno on my last post on Faults and Messages. Bruno asks “If two faults happen at the same time, will this procedure work?” This is a more complex question than it …
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