On Tuesday 26 July 2016 09:30:34 Gene Heskett wrote: > On Tuesday 26 July 2016 04:48:51 andy pugh wrote: > > On 26 July 2016 at 09:00, Bruce Layne <linux...@thinkingdevices.com> > > wrote: > > > If your VFD will communicate via RS485, you should be able to plug > > > an RS232 to RS485 converter (about $8 delivered from Amazon) into > > > the serial port > > > > Or spend $2 and use USB. > > https://forum.linuxcnc.org/forum/18-computer/30675-on-motherboard-mo > >db us-rs485-connection#72351 > > > > (This is about a hack that I made to one, but it worked > > as-delivered). Current eBay price is slightly less than £1. > > Looks good but isn't carrying a ground. I see dongles with 3 and 4 > terminals or a cable on the far end that I'd assume would allow, if > the VFD wants it, both a common ground, and a supply reference. I'll > check the VFD later today sometime. If it looks like it can, I'll do > it. > > Thanks Andy. > Humm, further reading says its not rs-485, but rs-232, with a very odd connection scheme. Looks like it has a +12 volt connection on what they are calling pin 1 of an 8 pin card edge connector that does not exist. With serial ground on pin 2, and 4 data transfer pins on 3,4,5,6 and two -12 volt connections on pins 7 & 8.
pc connections at a presumed db9 serial port are inverters pin 2<->5 on the db9. inverters 3,4 <-> 2 on the db9 inverters 5,6 <-> 3 on the db9 buss speed 9600 baud data 8n1 inverter sends 13 bytes inverter receives 9 bytes Since 9 bytes isn't anywhere near enough to initialize all 34 of its "Pins" I guess it must have some nvram in it. Another test of an hours powerdown by dropping the breaker, and it did remember what I had entered from the panel. Both directions seem to well loaded with synch and checksum bytes as the last 2 bytes going each way are the xor and additions of the previous bytes in the packet, and each starts with 0x00,0x55 and ends with an 0xFF. With enough stuff on the next page to define what the individual bytes represent. The control port pin defs don't seem to connect very well with its pin bucket #3 set to 6, which equals external digital control, and the interfaces pin 11 is marked D0+ and pin 12 is marked D1-. Confuzin. There is what looks like a spot on the logic board for a miniature usb or serial header, active circuitry looks like its populated around it, but the 9 pad, (one row of 4, one row of 5) thruhole style spot on the board is empty. It looks to be about half the size of a regular motherboard usb header. And the pad holes are smaller too. So I am not convinced it has the serial port, but if it will remember what I put in it during an extended power down, I can use it as I originally intended, with a run/stop, dir, and pwm into the 5 volt port. But its about as usefull as the teats on a boar hog if I have to spend an hour programming it everytime its powered up. I don't think it draws much power when fully stopped, but I sure don't think much of leaving it on 24/7/365.25 either. Just for S&G, I set it up for some ridiculous slow speed, and left it running at about 590 rpms (its a 1725 rpm at FL rated motor), at 20hz for about half an hour. One spot on the outer frame made it up to 111F on a 70F garage. I had a small amount of torque comp enabled below 45 hz, and the coil currents went up to about 3.6 amps (3.4 FLA on the label) but soon fell back to the 3.4 range as the coils warmed up. I tried to load it up by jamming a gob of paper towels against the pulley without having a hugely noticeable effect on the speed or the amps showing on the imitation amprobes, so it appears I can run it over a wider speed range than I had imagined. 16.6 rpms at the chuck anybody? OTOH, I have no clue what the frequency response of these clampon, digital imitation "amprobes" is, they, when not at 60 hz, could well be lying to me. One is a "Greenlee" & the other is an "Ideal" brand. I have tried to find some data on the net about that, without a lot of luck. FWIW, if both are on the same coil wire, they agree quite well. Both at low and high frequencies Can anyone else comment about this source of error in reading amps with these things? > Cheers, Gene Heskett 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> ------------------------------------------------------------------------------ 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 Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
