If there is such a demand: there are 8 same belt machine need simple start and stop control, press the start button belt operation, press the stop button belt stop.Of course, this is very simple without using structured variables and can be done in a few lines of ladder diagrams.Today, mainly through this simple example to illustrate how to establish structured variables, improve the efficiency of PLC programming.1. Design two PLC data types for belt machine control.2. Create variables according to the above PLC data types.Note: The above address assignment is word based.3. Configure hardware.Note: Hardware address and PLC variables corresponding relationship.4. Create a FB and write a program.Note: This is just a simple start-stop program, press the start button (I point), Q point is true;Press the stop button (point I) and point Q is false.5. Program call.Note: It can be seen that only 1 pin variable is required for each of the 8 belt machine inputs and outputs.Conclusion: The design of structured PLC variables can greatly improve the design efficiency, but also can reserve space for equipment expansion.Retweets are the biggest encouragement!Thank you for your support!Tips advanced family bucket: contains 18 classic books, years of electrical examination, electrical necessary training simulation software, electrical automation industry of various types of technical manuals!