I'm trying to get my Shizuoka going after being idle during the Summer. Some of the parts had "fallen" off. So, in putting it back together I attended to an issue that bothered me from before. The SPI DAC I use to feed the 0-10 V input to the spindle VFD wanders a bit and is enough to notice the speed change at the spindle. I suspect the problem is that the VFD and DAC have different supplies and grounds. I decided to try a different approach and rigged up an opto-isolator which switches the 10V speed supply to the 0-10V input. I feed the transmit side of the opto-isolator with a PWM signal. I get much less wander, but after adjusting the scale, I realized only the first 10% of the PWM range is used to get 0 to 100% RPM (10V). I would like to have 100% pwm correspond to 100% RPM or 10V input. I tried various resistors to limit the input current or to pull the input down, but I still get the same problem.
Has anyone setup a PWM input to a VFD that utilizes the full PWM range? If so, please let me know how it can be done. There is a 20mA input also, but I don't know how it is supposed to work. I'll check the manual, but hints would be appreciated. Otherwise, I my need to resort to a digital potentiometer. Thanks for any help. -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/index.html California, USA ------------------------------------------------------------------------------ All of the data generated in your IT infrastructure is seriously valuable. Why? It contains a definitive record of application performance, security threats, fraudulent activity, and more. Splunk takes this data and makes sense of it. IT sense. And common sense. http://p.sf.net/sfu/splunk-d2dcopy2 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
