Valve control and signalling problem over a single wire

A PIC or Dallas on both sides converting the signals to code (RS232 or...) can solve the problem. You will need more wires to supply power.

Having to supply power in any case you must consider superimposing the signals on the AC. This has been available for a long time.

Your using 100 v dc..

I have in the past been requested to do a similar application in an automotive application..

I used a pair of addressable (256) chips that allowed signals to be encoded and sent on the actual power supply wires, that is the signal content was encoded and decoded at the source and destination of the power supply, using no extra wires at all, the supply had to be dc though, as I believe your application is..

Even though the power supply impedence in this automotive application is quite low, that did not seem to affect the data we were communicating, this system worked very well, qute a lot of this application was manufactured and in use.

I did this approx 10 years ago, I would have thought better, or similar or same chips should be availabe now if researched.

I hope this helps.

All the best with you project.

There is a simple solution that does not involve anything so complicated as RS 232 coded signals , chips and the like but it involves a component that I have applied a patent protection. It does use AC power and selective current control along with my novel LED based current detector.

This very low impeadance detector will drive LEDs in the current domain alone over the massive range of +or- 3mA to 10 Amperes and represents an almost solid conductor that usefully lights up on current presence over this range while it derives its power from the line current and is even selective to its polarity.

As well as visible LEDs there are also 2 volt free outputs, I have called it INDI-LINK after INDIcating wire LINK and there is limited info. on the web if interested.

Does everybody give up and want the solution?

Idec makes a smart relay that will do this a PLC that is programmable it costs about 200 dollars

Yeah but bmine costs $20 in volume.