Never actually seen one, but this gadget looks sort of like the middle ground between a full up spectrum analyzer and just waving around an AM radio.
http://www.saelig.com/miva/merchant.mvc?Screen=PROD&Product_Code=EMC006 Cheers, Steve Stallings > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of Matt Shaver > Sent: Thursday, June 05, 2008 2:57 PM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] Request for information at the CNC Workshop > > > On Thu, 2008-06-05 at 00:18 -0500, Jon Elson wrote: > > I don't think there is truly ONE way to do things. You pretty > > much have to use safety-rated controls from Pilz, Crouzet, > > Schaffner, Faulhaber, etc., and then set them up so they can > > function correctly to stop motion, even after a component failure. > > Yes. In fact, that's what I've learned so far! The most recent control > I've built uses a commercial safety relay in the estop circuit, as well > as an EN418 qualified (anti tease, positive acting) estop button. > There's also some redundancy of power control elements and monitoring > circuits that prevent resetting estop if a contact has welded closed. > > What I'm interested in is what I've missed! I learned all those > techniques from manufacturers literature that refers to these standards, > but I've never actually seen the standards documents themselves, and I'd > like to... > > <...> > > pretty expensive. Then, you get into calibrated wideband > > antennas, and on and on. Finally, you have to test every > > different configuration, so you generally have to test each > > specific installation, if you are doing one-off machine retrofits. > > All true of course. I guess I put too much emphasis on the "accuracy" > part of my request. I don't doubt that elaborate test equipment and > facilities would be required to certify performance to a particular > standard or spec. > > The most basic test for RFI is to tune around the AM radio band on a > receiver with the antenna close to the equipment under consideration, > listening for changes in the level of "static". I'm just hoping to > improve on this; to take it to the next step. Maybe build some sort of > "hobby standard" wide band RFI detector useful for comparison purposes, > rather than a calibrated measurement instrument. > > For example, if I put a ferrite bead on a cable, did it help reduce the > RFI, or was there no change at all? Right now, I'm operating in the > dark, installing filters, chokes and beads in an anticipatory, > prophylactic way ;). What I need is a relative indicator to detect > electrical interference, locate the source, and compare the effect of > different mitigation methods. > > > Most machine tool controls have had totally uncontrolled > > emissions, because they were mostly exempt as heavy industrial > > equipment. Note the lack of output filters on most PWM servo amps. > > Your own being an exception to this! > > > Devices to inject disturbances into the line and equipment > > chassis are not as bad as the spectum analyzer type gear, and > > you can even make much of this yourself, like with auto ignition > > coils and pulser circuits. > > I did make a vibrating relay type noise generator which helped recreate > an intermittent problem with a spindle speed control board. Once they > were able to reliably produce the problem, the manufacturer of the board > was able to add hardware filtering and do some software modifications > that eliminated the problem. > > I want to come up with some reference designs for these types of noise > generators so that susceptibility comparisons can be made. > > Thanks, > Matt > ] > > > ------------------------------------------------------------------------- > Check out the new SourceForge.net Marketplace. > It's the best place to buy or sell services for > just about anything Open Source. > http://sourceforge.net/services/buy/index.php > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------- Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://sourceforge.net/services/buy/index.php _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
