Re: [Emc-users] Serial Encoders
On Mon, 2008-03-10 at 22:28 -0400, Stephen Wille Padnos wrote: Since you're convinced you want a quadrature encoder now, here's a link: :) http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=GH6102-ND I've used these before, and they're good, robust controls. They have detents (pretty good clicky ones), and the switch is also a pushbutton with a separate contact pair. They're good for setting something like spindle speed or FO, but probably not for something like a jogwheel (only32 counts per rev). At $20 each (probably less at non-DK distributors), I think they're a good deal. - Steve ($21 from the US Digikey) I like it. Plus the push to select feature is nice too. I am a little leery about the low counts per revolution. For eight bits of resolution, that would be, 256 bits per full scale/32 counts per rev. = 8 rev. In real use, is eight turns a bother? Actually, it might be safer. I did see this encoder: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=601VCS-ND at $30, with 128 counts = 2 turns, but no detent or select switch, though I suppose these could be added. -- Kirk Wallace (California, USA http://www.wallacecompany.com/machine_shop/ Hardinge HNC lathe, Bridgeport mill conversion, doing XY now, Zubal lathe conversion pending) - This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse012070mrt/direct/01/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
[Emc-users] Serial Encoders
I am looking into adding a knob for setting spindle speed manually. This serial encoder is close to what I am looking for: http://www.usdigital.com/products/a2/ but is over-kill and way too expensive. Does anyone have a link to an 8 or 10 bit serial (SPI like) absolute encoder? I checked Digikey but didn't find anything. Other options are to use a potentiometer and serial ADC or PWM to serial, but an inexpensive single unit would be better. Thanks. -- Kirk Wallace (California, USA http://www.wallacecompany.com/machine_shop/ Hardinge HNC lathe, Bridgeport mill conversion, doing XY now, Zubal lathe conversion pending) - This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse012070mrt/direct/01/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Serial Encoders
Kirk Wallace wrote: I am looking into adding a knob for setting spindle speed manually. This serial encoder is close to what I am looking for: http://www.usdigital.com/products/a2/ but is over-kill and way too expensive. Does anyone have a link to an 8 or 10 bit serial (SPI like) absolute encoder? I checked Digikey but didn't find anything. Other options are to use a potentiometer and serial ADC or PWM to serial, but an inexpensive single unit would be better. Thanks. I would not recommend absolute encoders (or pots with A/Ds, which are also absolute). Think about something like feed override, where the is a slider on the GUI as well as a physical knob. If you turn the knob, EMC will adjust the position of the slider to match. But if you move the GUI slider, it is impossible to turn the knob to match. If you use an incremental encoder with no scale, then it can coexist nicely with the GUI slider (or with other physical controls - for example you could have a knob at the machine control, and another knob located on the far side of a large machine table. Another example would be on-off controls like spindle or coolant. If you use a toggle switch, you can have only one. If you use start and stop buttons, you can have as many of each as you want. This concept of using incremental controls is a fundamental principle adopted by NIST when they were designing EMC. Think long and hard about the implications before you switch to absolute controls. Regards, John Kasunich - This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse012070mrt/direct/01/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Serial Encoders
On Mon, 10 Mar 2008, John Kasunich wrote: Kirk Wallace wrote: I am looking into adding a knob for setting spindle speed manually. This serial encoder is close to what I am looking for: http://www.usdigital.com/products/a2/ but is over-kill and way too expensive. Does anyone have a link to an 8 or 10 bit serial (SPI like) absolute encoder? I checked Digikey but didn't find anything. Other options are to use a potentiometer and serial ADC or PWM to serial, but an inexpensive single unit would be better. Thanks. I would not recommend absolute encoders (or pots with A/Ds, which are also absolute). Think about something like feed override, where the is a slider on the GUI as well as a physical knob. If you turn the knob, EMC will adjust the position of the slider to match. But if you move the GUI slider, it is impossible to turn the knob to match. If you use an incremental encoder with no scale, then it can coexist nicely with the GUI slider (or with other physical controls - for example you could have a knob at the machine control, and another knob located on the far side of a large machine table. Another example would be on-off controls like spindle or coolant. If you use a toggle switch, you can have only one. If you use start and stop buttons, you can have as many of each as you want. This concept of using incremental controls is a fundamental principle adopted by NIST when they were designing EMC. Think long and hard about the implications before you switch to absolute controls. Regards, John Kasunich I agree wholeheartedly with John. However if you do need an inexpensive absolute encoder, austria microsystems makes an interesting magnetic sensor with 8-12 bit precision for under $20: http://www.austriamicrosystems.com/03products/20_rotary_encoders.htm They have the magnets too. -fenn - This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse012070mrt/direct/01/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Serial Encoders
--- [EMAIL PROTECTED] wrote: From: ben lipkowitz [EMAIL PROTECTED] To: Enhanced Machine Controller (EMC) emc-users@lists.sourceforge.net Subject: Re: [Emc-users] Serial Encoders Date: Mon, 10 Mar 2008 17:46:26 + (UTC) ...if you do need an inexpensive absolute encoder, austria microsystems makes an interesting magnetic sensor with 8-12 bit precision for under $20: http://www.austriamicrosystems.com/03products/20_rotary_encoders.htm They have the magnets too. I used a quadrature encoder from a range control in a few experiments around here. Worked great for up/down stuff like spindle and feed override. Found one at an appliance repair shop with a 1/4 inch split shaft for a push on knob. Ray - This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse012070mrt/direct/01/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Serial Encoders
Since you're convinced you want a quadrature encoder now, here's a link: :) http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=GH6102-ND I've used these before, and they're good, robust controls. They have detents (pretty good clicky ones), and the switch is also a pushbutton with a separate contact pair. They're good for setting something like spindle speed or FO, but probably not for something like a jogwheel (only32 counts per rev). At $20 each (probably less at non-DK distributors), I think they're a good deal. - Steve Kirk Wallace wrote: I am looking into adding a knob for setting spindle speed manually. This serial encoder is close to what I am looking for: http://www.usdigital.com/products/a2/ but is over-kill and way too expensive. Does anyone have a link to an 8 or 10 bit serial (SPI like) absolute encoder? I checked Digikey but didn't find anything. Other options are to use a potentiometer and serial ADC or PWM to serial, but an inexpensive single unit would be better. Thanks. - This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse012070mrt/direct/01/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
