Jon, I believe you have a very clear idea how to make a program ;-) So, you make serially attached switches (homing and end switches) that each sends his own message in the same serial line. Use a differential current driven twisted pair with termination at each point. Basically you will want many senders and one receiver. Because the events will be asynchronous, each sending unit needs to have a different message repeat frequency. Well, you can even make it analog with each switch turning on injecting of a specific tone into the line! What you need to do the most is to calculate what transmission and repeat speeds would be most useful. But I think about 1 Mbaud would be adequate even for fast homing. ... still another wonderful option is a pulse train technique. That one is colisionless.
Bidirectional pulse train would be similar to the one used in RC models, but here you would be injecting series of shorter pulses, say 1 unit of width with a pitch of say 3 width units. The train would be repeated each 40 time units and driven and initiaded by the master. Such configuration allows you to use say, 10 switches safely. Now how that works is, that the switch logic is able to determine which pulse in the train came because there is a longer period of quiet signal before each retransmission. Now that the time comes the switch logic is able to extend the pulse duration by one time unit, during which any receiving end may understand it. Or you may do it with the pull-up method where the pulsetrain send will use wide pulses, whose ends will be cut by shorting down. That variant might be even able to run out of a single twisted wire pair! On 4/26/08, Jon Elson <[EMAIL PROTECTED]> wrote: > John Kasunich wrote: > > > > Unfortunately I don't have any connector suggestions. But I do have an > > observation: Every AC servo motor I have ever seen uses two connectors > > and two cables - they do NOT put the noise sensitive encoder signals in > > the same bundle as the noise emitting motor power leads. > > Obviously you wouldn't want them inside the same shielded cable, > for instance. No argument there. I have had no trouble running > these in the same connector, where the signals are only nearby > for 2 inches or so. Also, I'm not working with 400 V drives, > more in the 80 - 120 V range. > > > Jon > > > ------------------------------------------------------------------------- > This SF.net email is sponsored by the 2008 JavaOne(SM) Conference > Don't miss this year's exciting event. There's still time to save $100. > Use priority code J8TL2D2. > > http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone > _______________________________________________ > Emc-developers mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-developers > ------------------------------------------------------------------------- This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Don't miss this year's exciting event. There's still time to save $100. Use priority code J8TL2D2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
