i have the digital version of this cape but i need to keep free the opto and pwm output for future project. So Marius (the furaday author) help me for manage PWM from Digital output 0 so this is 24v pwm with my setup. (for reverse F/R and enable i use also digital output)
I not fully understand it is ok for use the amazon board you found for convert my PWM to 0/5v PWM (with try to invert pin) and use 2 other channel for enable and direction for the ebay controler? Than you suggest i now think is better to not use the rs232 except for make all more complicated. Thanks a lot Le mardi 16 juillet 2019 05:00:04 UTC+2, justin White a écrit : > > The Furaday cape says it has 5v PWM outputs on P1.... > > https://docs.google.com/spreadsheets/d/1D2rlEZcO0M6Qlk-UZ7ufp3wbE0IHuzRvnHuqvfVDcJY/edit#gid=1554435935 > > Maybe you're using a field output as PWM? If you can't get around that > these are cheap and worth a try..... > > https://www.amazon.com/24V-Optocoupler-Voltage-Level-Converter/dp/B01EY767S8?th=1 > > You can feed the 24v PWM into the input and it will output an inverted 5v > PWM. I don't have a BBB but looking at hal_pru the pwmgen component has a > scale pin and it looks like a value of -1 will invert the PWM and cancel > the boards inversion out if it matters which it probably doesn't. You can > just use an optocoupler output on that cape to pull the F/R pin to > speed_gnd on the driver board to change directions. > > The cape handles 0-5v analog outputs as well so you could use that too. > > The KB drive is just a PIA at that point. You can use the serial thing but > I'm not sure what difference you think it makes. The only thing that serial > can do is command a speed output to the driver board. You still have to > close the loop with feedback coming from something else, like an encoder > which doesn't change regardless of whether you use PWM/serial/or analog. If > you command a speed of 300rpms No matter which you choose all it can do is > command an output that you tune to be as close to relate to 300RPM as you > can. So if you go to take a cut and the spindle bogs down there is no way > to detect that unless you have an encoder and run a PID loop. The PID will > compensate for the slowdown by increasing or decreasing the output command > to hold steady, it could be a serial command to speed up, a PWM duty cycle > increase, or an analog voltage increase, it doesn't matter if the PID is > setup right. > > Analog is a bit more susceptible to noise than PWM. Serial is fine if you > really want to deal with it but I'm not sure I see why you would. It looks > like if you configure the outputs on your BBB/cape right all really don't > need anything extra. > > On Monday, July 15, 2019 at 9:31:48 PM UTC-4, Aurelien wrote: >> >> Yes i have found this controler firstly by schearching something with PWM >> input and possible reverse. >> >> My problem with the ebay controler is to convert my furaday 0/24v PWM to >> 0/5v PWM isolated, unfortunatly i'm not able to design something like this >> myself. >> The seller send to me only the 3 first attached documents after waiting >> and ask again and again from 4 month. >> (edit : i have think about keep the k24p-10v with the ebay controler and >> use the reverse function the easy way) >> >> The KBMG is retrofited when start the project, in reality i like to keep >> this controler if i can found for reversing (maybee find someone and pay >> some money for a ready to use solution for this one or for the PWM ebay) >> >> For the suggestion about retrofit AC motor it's i think for a lathe with >> motor integrated to the spindle this not the best way. >> >> Many thanks for your interest >> >> >> Ps : Finally you think it is better for spindle accuracy to have a simple >> PWM (or PWM/analog) with pru or a complex C code comp file with serial >> communication or this is only more easy to use PWM ? (I'm lost : finalize >> the order or not lol) >> > -- website: http://www.machinekit.io blog: http://blog.machinekit.io github: https://github.com/machinekit --- You received this message because you are subscribed to the Google Groups "Machinekit" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. Visit this group at https://groups.google.com/group/machinekit. To view this discussion on the web visit https://groups.google.com/d/msgid/machinekit/0d439b21-1fbc-462b-b568-9e7e30f579f5%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
