On Mon, 7 Dec 2020, Todd Zuercher wrote:
Date: Mon, 7 Dec 2020 19:08:00 +0000 From: Todd Zuercher <[email protected]> Reply-To: "Enhanced Machine Controller (EMC)" <[email protected]> To: "Enhanced Machine Controller (EMC)" <[email protected]> Subject: Re: [Emc-users] Mesa Tacho Generator?Mostly, I was hoping to avoid the thread delays of having to go through hal adding 1-2 more thread cycles to the "staleness" of the data. (Encoder read/process to velocity, Hal read from Mesa, Hal process value/scale, Hal write back to Mesa), and was just curious if it had been tried before.
There is less than one thread delay in the "read, process, write" path since all operations would be done in a single invocation of the servo thread, though the velocity would be the average of the velocity from the last servo thread invocation to the current one. (assuming proper thread order). The bandwidth of course would be limited by the servo thread rate.
Todd Zuercher P. Graham Dunn Inc. 630 Henry Street Dalton, Ohio 44618 Phone: (330)828-2105ext. 2031 -----Original Message----- From: Peter C. Wallace <[email protected]> Sent: Monday, December 07, 2020 1:08 PM To: Enhanced Machine Controller (EMC) <[email protected]> Subject: Re: [Emc-users] Mesa Tacho Generator? [EXTERNAL EMAIL] Be sure links are safe. On Mon, 7 Dec 2020, Todd Zuercher wrote:Date: Mon, 7 Dec 2020 14:47:56 +0000 From: Todd Zuercher <[email protected]> Reply-To: "Enhanced Machine Controller (EMC)" <[email protected]> To: "Enhanced Machine Controller (EMC)" <[email protected]> Subject: [Emc-users] Mesa Tacho Generator? Is it possible to set up a firmware for a Mesa FPGA that could read the encoder velocity from an encoder input and output that velocity as an analog command directly to an analog output (hopefully at faster than the servo thread rate) in order to bypass having to do that connection in Hal? Can the analog outputs of any of Mesa's daughter cards be updated faster than the Servo-thread rate?Its possible but a fair amount of work, I would try servo thread operation first (4KHz or so servo thread operation is possible with a decent CPU and PCI/PCIE cards) There are a number of people that have done this with decent results Note that the encoder velocity estimation uses delta_count/delta_time calculations where delta_time is the time between counts (_Not_ the sample time) so the quantization noise is much lower than the +-1 count you would have with a delta_count/sample_time velocity calculation.Todd Zuercher P. Graham Dunn Inc.<http://www.pgrahamdunn.com/index.php> 630 Henry Street Dalton, Ohio 44618 Phone: (330)828-2105ext. 2031 _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-usersPeter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your (")_(") signature to help him gain world domination. _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
Peter Wallace
Mesa Electronics
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