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
