On Sun, 28 Oct 2018, Chris Albertson wrote:
Date: Sun, 28 Oct 2018 10:41:14 -0700 From: Chris Albertson <[email protected]> Reply-To: "Enhanced Machine Controller (EMC)" <[email protected]> To: "Enhanced Machine Controller (EMC)" <[email protected]> Subject: Re: [Emc-users] 5I25-7i76 encoder outputOn Sun, Oct 28, 2018 at 5:15 AM andy pugh <[email protected]> wrote:On Sun, 28 Oct 2018 at 07:17, Chris Albertson <[email protected]> wrote:Or switch to the other method. Rather then count "ticks" you count the microseconds between the ticks.The Mesa encoder counter already does this.Then perhpas this is the wrong method. There are two ways to go and which to pick depends on the encoder and how fast it spins. If you are counting microseconds then just maybe that's the wrong way to go for a high reasolution sensor that is spinning fast. For a high resoultion sens toy can coubtstincks per sample period. You'd like to have at least 100 ticks per period. Perhaps there are not enough microseconds betwen pulses. You'd like to have at least 100 timer counts --
The Mesa Encoder uses both methods combined = delta_counts/delta_time, so for example if you have 7 counts between servo thread times, the velocity will be calculated as 7/(time from first to last edge of those 7 counts)
This is optimum for most uses.Some fancier systems automatically compensate for quadrature phase errors and duty cycle variations.
Chris Albertson Redondo Beach, California _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
Peter Wallace
Mesa Electronics
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