logixpro traffic light exercise 2 solution

We all know that a PLC will not be used to control a traffic light, but if it was, and it quit with the lights green for one direction, or even both red, that is not so bad. You are doing yourself a favor, as well as anyone who follows you.įrom past experience fooling with the LogixPro Traffic Light, if there is even a small gap between lights, accidents will occur and the bodies will pile up!īest to leave it like you have it. Other PLC Vendors have their own ways of doing things, but most have a mechanism for commenting the PLC Code, and it should be used. I found them very useful in 5 and 500 Programs. This is used throughout the program for timed events.' For Allen Bradley, something missing from RSLogix 5000 is Page Titles. How about something like 'The next 3 rungs fetch the PLC Real Time Clock, and converts it to six Integer Values. Now that doesn't mean you have to comment every rung, especially if you are repeating yourself. Way too much water under the bridge for that. Or even yourself, I don't remember PLC Code verbatim that I did 2 years ago. Just because it made sense to you, doesn't mean that it will the next person who has to look at it. Yes, Ladder Logic is generally a little more obvious, but there are many many ways of achieving the same thing. I have even had to work on programs with no annotation whatsoever, and believe me, it was not fun. The tools are there, use them! I have had to use programming Panels and software that had little or no mechanism for commenting, and it was a pain.

I learned my lesson, and as I moved up through higher languages, I made sure everything was commented. How do you think someone else is going to do? My first efforts were not commented, and I did not have a clue what I was thinking when I wrote it. I started programming in 8080 Machine Code, and have gone back a few months later. That does not mean you should not comment your code. Good annotation and/or Tags help a lot, and should be encouraged. Your statement was effective communication - I just don't fully agree with it. Long winded, techno-jargon, business-speak morons who think they are the 'Great Communicator' and go on and on for thirty minutes without communicating anything really get my goat.

The key word there is 'effective.' It is one of the hardest things to accomplish. It dosen't matter if that communication is comments within a PLC program, a chat with a son or daughter, a letter to a customer and so on. However, EFFECTIVE communication is the most important aspect of our lives. If the comments are meaningless (see the comments on rung 5 & 6) then they are useless. I both agree and disagree with you about comments. I can redo the LIM statements so that there is a. The only thing that I could see as an issue is the fact that if the PLC stopped running and the timer was at 20, 100, 160, or 240 that you would have multiple lights on at once.

Logixpro traffic light exercise 2 solution