gene heskett wrote: > On Saturday, January 22, 2011 10:39:48 pm Edward Bernard did opine: > > >> I'm currently working on a stand-alone stepper controller based on an >> Arduino. As I get further into this I'm feeling the need for an >> oscilloscope so I can actually see if my code is giving me the results >> I want. Not having one at my disposal I got to thinking that I could >> use Halscope somehow. Is this possible? Any ideas of how to accomplish >> it? >> >> Greg >> >> >> > Someone may call me out, but I believe halscope doesn't have any inputs > from the outside world. > Sorry, but I have to.... While Halscope itself can only read internal signals, anything you want can, in principle, be piped into the Hal environment. What you'd do is set up a base thread at some suitable rate, and run Halscope and the parport module on that thread, with the parport data bus set to input. Then, you could have Halscope bring in those signals for display. Now, whether this is worth all the trouble to set it up is a good question. On the other hand, if at some point somebody wanted to see how some device was performing when commanded by EMC to produce some signals for moving something, then it would be the ideal way to analyze the system. You could see internal EMC signals related to motion, the commands sent to the device, and the step pulses or whatever produced by the device.
Now, if you want an analog scope, it gets much harder, but Greg was wanting to see step pulses, so that would be easy with the parallel port. > I would tend to go shopping for a decent, at least dual trace, 100mhz scope > and some decent 10x probes, (check MPJones for decent, reasonably priced > probes) mainly because the chopper waveforms present in a modern drive need > at least that amount of bandwidth in order to be able to reproduce what is > going on, allowing one to study dead times and such. These circuits often > have sub 10 nanosecond rise and fall times & that means 100 mhz. Or more. > Well, an analog scope can be quite useful when measuring repetitive events. It can also be a HUGE pain when measuring single-shot events, as are really common when debugging motion systems. So, a digital storage scope is a real boon if you are going to do a lot of this work. If all you need is to see digital signals, then maybe using Halscope through the parallel port might be OK, assuming a 50 KHz sampling rate is adequate. > Steer clear of older tektronix scopes (2235/545's etc) as their custom made > input attenuators go out of calibration in ways the scope probes capacitor > adjustments cannot cope with. And they are not repairable as those parts > aren't available after 5 years, about the same time it needs fresh ones. Well, Tek had two lines, the economy line and the "pro" line. Yes, the 22xx series was the economy line, and most now probably have non-repairable problems. The 24xx line were more expensive new, but can be had fairly reasonably, now. I had a B&K for years that finally died, and I have replaced it with a Tek 2465. These have one of the best writing rates (means: bright display even on slow rep-rate signals) on any analog scope, ever, without going to microchannel plates, which you DON'T want! But, really, for motion system debugging, I'd MUCH rather have a digital storage scope. You can capture a single-shot event and sit and look at it as long as you like. Jon ------------------------------------------------------------------------------ Special Offer-- Download ArcSight Logger for FREE (a $49 USD value)! Finally, a world-class log management solution at an even better price-free! Download using promo code Free_Logger_4_Dev2Dev. Offer expires February 28th, so secure your free ArcSight Logger TODAY! http://p.sf.net/sfu/arcsight-sfd2d _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
