On Sunday 18 October 2020 22:21:11 Chris Albertson wrote: > Gene, > > Read the first page of the data sheet. It says near the end of the > first page... > > *The speed of the motor can be controlled in all possible conditions > by the > > > PWM up to kHz. In all cases, a low level state on the PWM pin will > > turn off both the LSA and LSB switches. When PWM rises to a high > > level, LSA or LSB turn on again depending on the input pin state.* > > What they are saying is that PWM acts like a master switch and when > low it opens-circuits the entire h-bridge. When PWM is high then > whatever switches are turned on by INA and INB are as you'd expect. > (Yes, they dropped the number of khz, a typo in the data sheet.) > > I've got a pile of these chips and this is exactly how they work PWM > controls the current in the motor and is effective speed control. > At about 10% PWM the motor starts to overcome its internal friction > and starts to move at 100% the motor turns as if connected directly to > a battery.
olimex boards have arrived. But am in bad need of hookup schematic to drive it with LCNC. It looks as if it takes at least 8 wires to hook it up. Since there are only 2 from the pwmgen, it looks as i I need some sort of a simple interfaceing board to connect them together. Bare minimum of dir and its complement. To be applied to the enaA and enaB for direction control. Looks like 2 comp modules looking at the pidA output but with reversed inputs. And a wee bit of historesis for deadband braking. In addf order immediately after pidA. Actually, use the existing pwmgen dir sig for reverse, and a comp for forward. But that won't give a simetrical(sp) deadband brake. Got a better idea? 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 [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
