Clay B.
Lifetime Supporting Member
I do not think anyone is saying the traffic light is the very "first" thing you should learn to do with a PLC. It is however a good "beginning" step. As some one posted getting one input to fire one output is really where you start.
I think in the U.S. the traffic light "series" is a good place to start because when you get things wrong it is very obvious. If lights do not change as they are supposed to almost everybody can visualize a car chrash.
I guess where it getes schewwed is when people make the system as complicated as possible right from the start.
Ironically, I have sat thru several classes on different brands of PLC's where making traffic lights was the goal. As you add things like car sensors, pedestrian push buttons you really get a feel for the way the PLC behaves. Plus if you have a good simulator, it can be quite entertaining when you find your errors.
My nefew and I have spent hours in the garage playing with this. We use a Micrologix PLC and a EZ-touch HMI. I created Multistate images to represent the lights and all the other indicators and sensors you would find at an intersection. After awhile my nefew added images of cars and even created crash routines.
I think in the U.S. the traffic light "series" is a good place to start because when you get things wrong it is very obvious. If lights do not change as they are supposed to almost everybody can visualize a car chrash.
I guess where it getes schewwed is when people make the system as complicated as possible right from the start.
Ironically, I have sat thru several classes on different brands of PLC's where making traffic lights was the goal. As you add things like car sensors, pedestrian push buttons you really get a feel for the way the PLC behaves. Plus if you have a good simulator, it can be quite entertaining when you find your errors.
My nefew and I have spent hours in the garage playing with this. We use a Micrologix PLC and a EZ-touch HMI. I created Multistate images to represent the lights and all the other indicators and sensors you would find at an intersection. After awhile my nefew added images of cars and even created crash routines.
