ladder logic

BRX Do-More PLC First Program (Start, Stop, Jog)

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We will now look at writing our first program for the BRX Do-More PLC. The Do-More Series allows us to write programs online or offline with the PLC controller. The series will also allow us to do online editing. We can change program information and download the new program between scans of our controller. As … Read more

PLC Program Example – Shift Register (Conveyor)

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We apply the five steps of PLC development to a plc shift register example. This PLC programming example will use a shift register to reject a product on a conveyor. When programming a PLC, you need to track what has previously happened. Shift registers allow you to do just that. We will look at a … Read more

PLC Programming Example – Process Mixer

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We will apply the five steps to PLC Program development to our following programming example of a process mixer. The process mixer will be programmed using ladder logic. We will discuss each step of the PLC program development. 1 – Define the task: How does the process mixer work? A normally open start and normally … Read more

How to Make a One-Shot in the PLC

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A one-shot in the PLC will turn an output on for one scan. This is used to trigger events that should only happen once. An example of this would be to increment a value in memory. If a one-shot is not used, then every scan of the PLC will increment the value. What is a … Read more

Creating a Flip Flop Circuit in the PLC

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A flip-flop circuit in a PLC usually has one input and two outputs. When the input is activated, the two outputs alternately latch on/off opposite each other. It is used to toggle (latch) work on and off with just one input. In the PLC, it is a single input that will toggle an output on … Read more