On Sunday 18 October 2020 22:21:11 Chris Albertson wrote: Advice on the OLIMEX board for a motor driver.
I have it wired up, I think. Grounded to system ground on pin 3, system logic 5 volts on pin 2. With complementary 5 volt dirs feeding ENA/ENB on pins 4-5 and a 5 volt pwm on pin 6, the motor on its terminals and a 24 volt psu on its set of terminals, pins 1-7-8 aren't connected. It will bring up the leds according to the dir sigs, modulated by the % of pwm. The motor is not moving at up to about a 20% pwm at 10 kilohertz, and above 20%, it disables the outputs until a powerdown is done. I'm switching all the motor power off with the f2 key, so 15-20 seconds off to let all the switchers bleed off seems to reset it ok. Pins 7-8 are sitting just a few millivolts above ground which looks duff to me since they have 3.3k on-board pullups to the 5 volt line. But thats how it powers up. It does warm up when the output direction leds are lit, but nowhere near too hot. So I'd assume some current is flowing, just not enough to move the motor. Obviously I'm doing something wrong, but what?. Do I need +5 volts fed to pins 7-8? I am NOT impressed with the pushbutton terminals OLIMEX uses, they do not grab a wire heavy enough to carry the expected 10+ amps of currant to keep a good connection if the wire moves. And its damned sure NOT a long term gas tight joint. I may yet pull them out and replace them with the green screw terminal plugs. Something I can put some serious torque on. The 150 watt audio class D can make quite an effective hand massager out of this motor at 20 hz, its dc powered and doesn't get warm doing it. The 430 watters need an AC supply, and don't work at all with DC from this supply fed to its FW bridge power input, so apparently it needs a balanced + and - supply. Either would need a d/a to feed a bypass the input hf pass filter that wants to protect the speakers. But other than a spinx1 that would be too slow, I don't have a D/A to drive them with. But its a thought and the 150 watter can seriously hammer that motor. So thats a potential what if. :) Thanks Chris. 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) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene> _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
