Not correct PDM is Pulse Density Modulation. Meaning that the period stays constant at the 1/frequency. The pulse width remains the same but the number of pulses per period changes. The pulse positions also remain static, meaning that if there are only three pulses (30% duty cycle) they will occur in the beginning of the period and leave the rest of the period void of pulses. So when you look at it with a scope you will see bursts of pulses at a regular interval. The number of pulses will increase as the command increases intil the period is fiulled up with pulses. So at 100% dutycycle requested you will get a pulse train that is continuous but at a very small PWM. Ten pulses in all per period for 100% duty cycle.
Not what I want. ------ Original Message ------ From: "Karlsson & Wang" <[email protected]> To: "Marius Liebenberg" <[email protected]>; "Enhanced Machine Controller (EMC)" <[email protected]> Sent: 2015-11-09 15:56:58 Subject: Re: [Emc-users] PWMGEN in PDM mode and not PWM >PDM I am pretty sure should be fixed. Then number of pulses increase >with increasing speed it may be the encoder signal? > > > >On Mon, 09 Nov 2015 12:29:12 +0000 >"Marius Liebenberg" <[email protected]> wrote: > >> Hi All >> I have a pwmgen setup to take the spindle command to generate a pwm >> signal. What I see on my scope is a PDM signal. I.E. the number of >> pulses increase as I increase the speed. I nee it to be PWM. >> I tried type=0 and type=1 when I load. Is there naother setting that >> does not get mentioned in "man"? >> >> The reason for using another pwmgen is beacuse I have to set up >>manual >> pulses for a spesified period. Not the usual spindle operation. >> >> ----------------------------- >> Regards / Groete >> >> Marius D. Liebenberg >> +27 82 698 3251 >> +27 12 743 6064 >> >>------------------------------------------------------------------------------ >> Presto, an open source distributed SQL query engine for big data, >>initially >> developed by Facebook, enables you to easily query your data on >>Hadoop in a >> more interactive manner. Teradata is also now providing full >>enterprise >> support for Presto. Download a free open source copy now. >> http://pubads.g.doubleclick.net/gampad/clk?id=250295911&iu=/4140 >> _______________________________________________ >> Emc-users mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ Presto, an open source distributed SQL query engine for big data, initially developed by Facebook, enables you to easily query your data on Hadoop in a more interactive manner. Teradata is also now providing full enterprise support for Presto. Download a free open source copy now. http://pubads.g.doubleclick.net/gampad/clk?id=250295911&iu=/4140 _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
