--- On Wed, 3/16/11, Viesturs Lācis <viesturs.la...@gmail.com> wrote:
> From: Viesturs Lācis <viesturs.la...@gmail.com> > Subject: Re: [Emc-users] pwm AD converter > To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> > Date: Wednesday, March 16, 2011, 9:51 AM > 2011/3/16 Klemen Dovrtel <klemen_dovr...@yahoo.com>: > > Hello everybody, > > > > I would like to measure some analog signals using emc > (for PID control). I think the easiest way would be to > measure the pwm signal. > > > > Is there a hal module/component which could i use or > can assemble one from existing hal modules/components? > > > > I was thinking i could use two oneshot functions, one > to trigger on rising edge and one to trigger on falling > edge. What i need is a function to measure the time between > those two events - is there a hal function for that? > > > I am not sure, if I understand correctly, what is the goal > You want to > achieve and what signals do You want to measure, but I > think that You > can: > 1) use voltage-to-frequency converter chip like this: > http://www.national.com/mpf/LM/LM231.html#Overview > or use already assembled Mesa's THCAD board > Both if them take 0-10V on input and outputs frequency > signal > 2) use encoder module in HAL to treat the frequency signal > and provide > an input to PID loop. > > Viesturs > > Thank you, this is what i was looking for :) But i am still not sure how to measure the pulse width with the encoder module. So i should use the stepgen module to generate pulses as fast as possible and count them using encoder module. I should reset the encoder module on rising edge of PWM signal and count pulses till the falling edge of PWM signal occurs. What i am missing is some function to hold the value of the encoder at time of falling edge. Regards Klemen ------------------------------------------------------------------------------ Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
