PLC Control of Layout

This is an explanation of how I modified the CW80 to allow for PLC control. The feedback and throttle control was an initial design so the numbers shown are not accurate. I discovered later one that the input to the CW80 is not a range of 0 - 3.3VDC for throttle but actually 0.90VDC to 2.90VDC and it is inverted. (2.9 volts is zero throttle) But this video explains the modifications involved to remotely control the CW80. This was based on the schematic that was published here years ago (although it is for the original CW80 and not the later one)

After I made this video, I adjusted the calculations in the PLC to provide the correct range of voltage to the CW80

https://youtu.be/yL8OVnO6Wh4

Mike

This video was after I adjusted my calculations and also shows the manual control of the throttle in the downgrades using diodes to drop the voltage in steps to control the speed of the train. With PLC control I can also increase throttle when the train goes in an uphill section of track.

https://youtu.be/XRoyLN8NaxE

Mike

Mike: I remember when you started out on this project. It's come a long way since then. Very impressive. Keep it up!

I posted some of my progress years ago when I started it and there seemed to be no interest in it so I stopped posting. I only posted again because I figured out how to hack the CW80 for remote control and thought someone might find the information useful. There are more videos of my progress on my channel.

Side & Team Train Interchange

https://www.youtube.com/watch?v=MZiGG264q4o

Train Operations Demo

https://www.youtube.com/watch?v=hqwPICviN0U

Here is some information if you want to remotely control a CW80. The input range for the CW80 via the throttle wiper is 0.90 volts to 2.90 volts. The input is inverted, 2.90 volts is zero output throttle, 0.90 volts is full throttle.

I measured this using a signal generator as an input to the CW80 and plotted the results. The feedback from the throttle was taking the output, converting it to DC, and then using a voltage divider to make the range 0-10 volts since that is the input range of the analog input of the PLC I am using. Now the CW80 is not a clean sine wave output, its more of a triac output so the feedback is not 100% accurate.

If anyone watched my video of the hardware of the PLC project, I am using a signal isolation for the CW80 input for throttle. The reason for this is there is a 24volt power supply that the PLC and related hardware uses and the DC- is connected to the track common "U" terminal of the CW80. This is so I can utilize block detection. It turns out the DC COM of the CW80 is *NOT* the same as the "U" terminal. The only schematic I have of the CW80 is the original version where the "A" and "B" terminals were common. I know for a fact I am using the second revision CW80 where the "U" are common, but I could not find an updated schematic for it.

When I originally tried connecting to the DC COM of the CW80 for the wiper, it blew out the internal fuse inside.

Hope this helps someone

Mike