I would strongly discourage any HAL component ever outputting a NAN value. No other HAL component (including the main motion controller) knows what to do with a NAN. What happens when NAN goes into a PID block? A summer? What is the calculated following error value when the feedback is NAN?
If a device can be in a state where its output is invalid, then it should output some legal number (perhaps zero, whatever makes sense in the context of the device), but it should have a separate bit pin that says "output is invalid". That allows the system integrator to decide what he wants to do. Maybe disable servo amps, maybe estop, maybe nothing. John Kasunich On Thu, Sep 5, 2013, at 08:20 PM, andy pugh wrote: > Many SSI encoders (and similar devices) have a means to indicate that > the data is invalid. > Should the system pass NaN as the feedback in that case? > > I don't think that should be done at the driver level, but would a > mux2 with a NaN input work? > I think the source would have to be a special NaN providing comp. (It > could have + and - inf pins too, I suppose) > > -- > atp > If you can't fix it, you don't own it. > http://www.ifixit.com/Manifesto > > ------------------------------------------------------------------------------ > Learn the latest--Visual Studio 2012, SharePoint 2013, SQL 2012, more! > Discover the easy way to master current and previous Microsoft technologies > and advance your career. Get an incredible 1,500+ hours of step-by-step > tutorial videos with LearnDevNow. Subscribe today and save! > http://pubads.g.doubleclick.net/gampad/clk?id=58041391&iu=/4140/ostg.clktrk > _______________________________________________ > Emc-developers mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-developers -- John Kasunich [email protected] ------------------------------------------------------------------------------ Learn the latest--Visual Studio 2012, SharePoint 2013, SQL 2012, more! Discover the easy way to master current and previous Microsoft technologies and advance your career. Get an incredible 1,500+ hours of step-by-step tutorial videos with LearnDevNow. Subscribe today and save! http://pubads.g.doubleclick.net/gampad/clk?id=58041391&iu=/4140/ostg.clktrk _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
