On Sunday 27 January 2019 13:33:50 Gene Heskett wrote: > On Sunday 27 January 2019 11:33:39 Jon Elson wrote: > > On 01/26/2019 07:15 PM, Gene Heskett wrote: > > > I've about give up on controlling this VFD with a pwmgen > > > directly as I have no way to step the 5 volt pwm up to a > > > 10 volt pwm. > > > > Can you program the VFD so 5 V input is the top speed you want? > > If there is such a register, it is not adequately described in > English. At about 98% duty cycle, 5 volt pwm, it actually runs at > about 5400 revs, or half speed at half voltage=1/4 full speed, which > ought to be 6000 revs. But there appears to be a fixed loss at the low > end. I haven't measured the timings quite that accurately. This is > treating the pwm as an AVI input, there is no response when the input > is set for PWM but the waveform is only a rail to rail 5 volts. It > might work at 10 volts but I've no quick and dirty way to step it up > to 10 volts p-p. So there is a 50% nominal error I can't explain. > > So I'll just put in the c41. That will likely require I reeassign the > fwd wire to supply the bobs 5 volts to the c41 as input logic supply. > Then the question is, has the 12 volts from the vfd got enough currant > to run the relays, or do I have to break into my jury rigged 24 volt > fan supply for that 200 ma. TBD. > > Frankly, this is being a big enough problem that I think the first box > completed in this 2 box project, will actually go to the 6040 > interface. I've ordered another 7i76d from mesa, which has this > c41/spinx1 built in, so I will shortly have enough stuff to make both. > > > Jon
One final question. This vfd has a 12 volt output, but load it with the C41 it becomes about 5.5 volts, so since the shade tree fan supply if floating, I'm in the process of borrowing half of that lash up for its 12 volts, which should power the C41 including it direction output relays. So one final question, as its been 2 years since I wired up the sheldons vfd, a clone from ebay. So do I ground the direction desired, or feed it 10 volts? Which the vfd also has available although I've not measured it. I will when I get it back together. I'll use that 10 volts as the direction voltage if its in tolerance and the vfd needs a high to enable that direction. 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> _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
