On Wed, 13 Jul 2016, Leonardo Marsaglia wrote: > Date: Wed, 13 Jul 2016 16:57:38 -0300 > From: Leonardo Marsaglia <[email protected]> > Reply-To: "Enhanced Machine Controller (EMC)" > <[email protected]> > To: "Enhanced Machine Controller (EMC)" <[email protected]> > Subject: Re: [Emc-users] Semi OT: Can't measure Index pulse on encoder > > Hello Jon. > > Well, the encoders that are already installed on one of our machines are > labelled with the Index pulse. The thing is I can't read the pulse with > halscope for example. > > I just tried to use the home using only index pulse and apparently the > index pulse is working because the axis latches until it stops and it turns > always a single turn more or less eyeballing it. > > The strange thing is I that I can't trigger the scope with the index pulse > on LinuxCNC, and also I can't measure the index on my other encoders. I > guess I should try to wire them to a LinuxCNC pc and make home manually to > see if they work ok.
The index pulse of a high resolution encoder is very likely to be too short for LinuxCNC to sense without hardware help. Imagine a 1000 count encoder with a index pulse that lasts one 1/2 cycle (same slot width as encoder) The index pulse width would be less than 1 ms at any speed over 30 RPM so likely to be missed at a 1 mS servo thread sample interval of HALScope. That is it might occur between HALScope sample intervals Index hardware in an encoder counter latches or clears the encoder count on index and typically sets a flag to tell LinuxCNC that an index event has occured. Because of this, a LinuxCNC system with a hardware encoder counter will not miss the index even even though the counter is only polled at 1 mS intervals > > > > 2016-07-13 14:29 GMT-03:00 Jon Elson <[email protected]>: > >> On 07/13/2016 08:56 AM, Leonardo Marsaglia wrote: >>> Hello to all. >>> >>> We just tested some Heindenhain encoders and as happened with other >>> encoders we can't sense the index pulse. We tried to detect it with a 20 >>> nano seconds period on a digital scope but nothing happens. All the other >>> pulses are working perfect except the index one. >>> >>> I have to mention that this happened with other encoders too, but since >> we >>> didn't need to use them with index pulse on the other machines we just >> let >>> it that way and didn't worry about it. >>> >>> >> Well, if the scope does not trigger on it, and it triggers >> fine on the A and B, then it just isn't there! >> Now, of course, the index will only happen once per rev, so >> you have to make a full turn to see the pulse. >> Are you SURE these encoders actually have the index pulse? >> >> Jon >> >> >> ------------------------------------------------------------------------------ >> What NetFlow Analyzer can do for you? Monitors network bandwidth and >> traffic >> patterns at an interface-level. Reveals which users, apps, and protocols >> are >> consuming the most bandwidth. Provides multi-vendor support for NetFlow, >> J-Flow, sFlow and other flows. Make informed decisions using capacity >> planning >> reports.http://sdm.link/zohodev2dev >> _______________________________________________ >> Emc-users mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/emc-users >> > > > > -- > *Leonardo Marsaglia*. > ------------------------------------------------------------------------------ > What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic > patterns at an interface-level. Reveals which users, apps, and protocols are > consuming the most bandwidth. Provides multi-vendor support for NetFlow, > J-Flow, sFlow and other flows. Make informed decisions using capacity planning > reports.http://sdm.link/zohodev2dev > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your (")_(") signature to help him gain world domination. ------------------------------------------------------------------------------ What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic patterns at an interface-level. Reveals which users, apps, and protocols are consuming the most bandwidth. Provides multi-vendor support for NetFlow, J-Flow, sFlow and other flows. Make informed decisions using capacity planning reports.http://sdm.link/zohodev2dev _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
