as On Tue, Oct 22, 2019 at 11:07 AM Gene Heskett <[email protected]> wrote: > > Greetings all; > > Now I have to figure out how to drive then slowly. > > It seems like the obvious way is to set up a pwm driver running fast > enough to not make too much noise, and maybe even take advantage of my > carehart notches in my hearing by picking the rep rate to be 4 khz which > I can't hear at all. I can get that out of a 7i76 interface, probably at > logic levels or at field power levels. I fact I thought of driveing it > direct, but the running at 12 volts FLA is around 425 ma, and thats a > bit much, and would need a fast flywheel diode to protect the 7i76 from > the turnoff spikes.
I've bought quite a few brushed motor drivers on eBay. First off the L298 is from the age of dinosaurs. It uses bipolar transistors. Anything modern uses MOSFETs. If the product uses a heat sink, just ignore it. All these drivers are the same, more or less they are just an "H-Bridge" with some gate drivers. If you want to build a more complex driver you still are best off buying the H-bridge and incorporating it into your design because designing a good H-bridge is hard especialy if you want over current and overvoltage and reverse polarity protection. I buy the board then add control logic. Almost always the control logic I add accepts serial commands, talks to a quadrature encoder and runs a PID loop. But if you already have all that running on a PC then a simple then simply wire the pin to ground and put PWM on the other pin As for knowing the exact specs, the eBay listing typically gives the part number of the chip. Look up the datasheet. As for knowing what they sell, that is what you get from a single mom selling random stuff out of her apartment in China. (Yes that is a typical description or a Chinese eBayer) If you want to talk to real engineers who live in the US buy your driver board from Polou. THese are a first teir US company. They offer schematics, ful specs, and competent support. https://www.pololu.com/category/9/motion-control-modules I've bought a lot of their stuff. -- Chris Albertson Redondo Beach, California _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
