Sam, I'm not sure what the purpose of the 1 Hz sin wave modulation is. Why and what are you trying to show with that? John
> -----Original Message----- > From: Sam Sokolik [mailto:samco...@gmail.com] > Sent: November-24-20 8:21 PM > To: Enhanced Machine Controller (EMC) > Subject: [Emc-users] Interesting observations with a cheap bob's analog out. > > Granted.. I know these are pretty basic. You can usually find them for > under 10 dollars. They do work quite well though. I was working on some > youtube content and was goofing around with this bob and the printer port. > Setting up a pwmgen to test the analog out unearthed some things.. > > -It isn't very linear. lincurve is your friend.. It can be off by as much > as .5v over the range. > -it is sloooowwwww. It is most likely a simple low pass. The photo here > is of a 1khz pwm signal modulated by a 1hz (yes - hz) sin wave. You can > already see it is phase shifting. 10hz and it is attenuated to about 2v > p-p. > -the pwm frequency didn't really affect the linearness or performance. > > http://electronicsam.com/images/greenmachine/IMG_20201124_183913.jpg > > one of these bobs... > > http://electronicsam.com/images/greenmachine/IMG_20201124_183919.jpg > > Still pretty cool what you can do with the printer port still ('I'm not > dead yet!') and rt_preempt. (50us base thread) This could be why I wasn't > able to get a very tight spindle speed control on the little emco lathe. > (I am using this bob's analog out driven from mesa pwm) And you are > certainly not going to control an analog servo with it ;) > > sam > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
