On Tue, 19 Jul 2016, John Kasunich wrote: > Date: Tue, 19 Jul 2016 12:40:21 -0400 > From: John Kasunich <[email protected]> > Reply-To: "Enhanced Machine Controller (EMC)" > <[email protected]> > To: [email protected] > Subject: Re: [Emc-users] Semi OT: Can't measure Index pulse on encoder > > > > On Tue, Jul 19, 2016, at 08:20 AM, Leonardo Marsaglia wrote: >> Could it a disadvantage the use of a digital scope over an analog one?. I >> remember talking about scoping half bridges for an induction heater and >> somebody underscored the advantages of the analog scope over the digital in >> some cases, wich is why some people recommend having both of them. > > If set to auto-trigger, neither scope is likely to detect an index pulse. > > In that situation, a digital with deep memory, slow sweep speed (or roll > mode) and a glitch capture mode would do better than the analog. > > But the real answer is to switch from auto-trigger to normal trigger and > set the trigger source and level appropriately so the scope will trigger > ONLY when the pulse arrives. > > With the trigger properly configured, either analog or digital would > be able to detect the index pulse, but the digital would give you a > better look at it because of its effectively infinite persistence. > > Halscope cannot reliably detect ANY pulse shorter than its sample time. > If sampling in the servo thread that is usually 1mS, index pulses are > often much shorter than 1mS (depending on how fast the encoder > shaft is turning). > > If you are using a hardware based encoder counter (Mesa or PPMC or > other), the actual index pulse probably doesn't appear in HAL at all. > > What Halscope CAN do is look at index-enable which is driven high > by motion during the homing sequence (or can be disconnected and > manually driven high by a "setp") and goes low when the encoder > driver detects an index pulse.
There's a simple shortcut for testing index enable without disconnecting it: just sets spindle-index-enable true ( substitute your signal name for spindle-index-enable if different ) > > > -- > John Kasunich > [email protected] > > ------------------------------------------------------------------------------ > 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
