On Wednesday 01 February 2017 17:41:00 Luke Kenneth Casson Leighton wrote:
> On Sun, Jan 29, 2017 at 6:48 PM, Gene Heskett <ghesk...@shentel.net> wrote: > > On Sunday 29 January 2017 12:40:21 Alan Corey wrote: > > > > Alan, ALL of the motor drivers are switchmode, with the current > > regulation running at or above 20 KHz. And these noise spikes are > > ringing at nominally 100 MHz. I have managed to get the xy motor > > noise under control by takeing out the switchmode psu's, and putting > > in tordoid transformers, bridge rectifiers, and the biggest > > electrolytic I had in the drawers that had sufficient withstand > > voltage. Its a star ground system, and the output cables to the > > motors are shielded, and the shield grounded as it goes by this > > single bolt ground on its way out of the box. The shielding extends > > both ways from that point but is not connected either at the motor, > > or at the driver, just at the bolt. This is std in such noisy > > machinery. > > i'm going to be looking at setting up an open hardware lathe and cnc > machine at some point, so i'm really delighted to see what you're > doing... i'm just really very confused as to why you're using such a > low-cost board from a *known* unethical fabless semiconductor company > to control such really very expensive equipment. just sayin. > > anyway: when working for Path Intelligence we learned the hard way > about R.F. and EMI interference, so we had to nickel-copper paint the > entire interior of the IP66 box and replace its rubber gasket in the > lid with a conducting one. > > we also got a 2nd-hand spectrum analyser, our resident expert made a > probe out of a single 20mm loop of copper wire exactly like you see in > the fairground attractions in days of yore, and we could confirm > immediately the effectiveness of anything that we tried to do. which > was really *really* effective in the case of the nickel-copper spray. > > i can therefore strongly recommend trying the same thing... but > honestly, the cost of all this equipment should be far in excess of > just replacing the entire board, including the processor that's made > by the unethical company known as broadcom, so i have to ask, > particularly given that it's so problematic, if you'd given that some > thought as a first priority rather than a last? > > l. Because its cheap at $35, the interface card is only $60 USD, and once the noise is nailed down, has the feel of something that will run until the next power bump. And right past that if I put a small ups on it as I have a 20kw nat gas fired standby just outside the back door? The ups would only have to hold up 3 or 4 seconds while the standby fires up. Where else can you get a machine controller capable of carving a Toyota racing engine out of a solid alu casting at a rate to keep up with the TRO demand? Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene>
