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. -- 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
