Re: [Emc-users] Possible lathe spindle encoder.
Has anyone found a source for the ATS694? Digikey doesn't have a listing... > -Original Message- > From: andy pugh [mailto:bodge...@gmail.com] > Sent: Wednesday, July 29, 2015 3:38 PM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] Possible lathe spindle encoder. > > A useful allegro publication, google for AN296089 (I can't seem to get a link out > of google) > > -- > atp > If you can't fix it, you don't own it. > http://www.ifixit.com/Manifesto > > -- > ___ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Possible lathe spindle encoder.
http://www.allegromicro.com/~/media/Files/Technical-Documents/AN296089-Crank -Sensor-ICs-for-Start-Stop-Application-Note.ashx The addin at https://addons.mozilla.org/en-US/firefox/addon/google-search-link-fix/ seems to fix Google's tracking "feature" that obfuscates proper links. > -Original Message- > From: andy pugh [mailto:bodge...@gmail.com] > Sent: Wednesday, July 29, 2015 3:38 PM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] Possible lathe spindle encoder. > > A useful allegro publication, google for AN296089 (I can't seem to get a link out > of google) > > -- > atp > If you can't fix it, you don't own it. > http://www.ifixit.com/Manifesto > > -- > ___ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Possible lathe spindle encoder.
Andy, Thanks for the info about how the cars came to use a missing pulse. I love how these historic things come back around. It's great that the standard railroad gauge is set to the width to the wheels of a roman war chariot. jerry On Wed, Jul 29, 2015 at 12:21 PM, andy pugh wrote: > On 29 July 2015 at 19:42, Jerry Scharf wrote: > > The "dual channel" is the independent output of the two hall effect > > transducers (available only in the surface mount part.) The other two > > outputs are direction (simple binary pin) and speed. Speed is the XOR of > > the two transducers, so it produces a full square wave for each magnet > pass > > under the device. You can then either time between edges of the square > wave > > to get an instantaeous angular velocity or between square waves to get > the > > rotation rate. Way easier that looking for a missing pulse. > > > > Most LinuxCNC applications (especially a lathe spindle) need an index > pulse. > Car engines need an index pulse too, but they do that by having a missing > tooth. (traditionally it was a shorter tooth on the starter ring-gear). > > 26.5 is absolute max voltage. The normal working range is 5 to 24V, so it > will work in just about any automotive application. > > -- > atp > If you can't fix it, you don't own it. > http://www.ifixit.com/Manifesto > > -- > ___ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > -- Jerry Scharf FINsix IT 650.285.6361 w 650.279.7017 m -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Possible lathe spindle encoder.
A useful allegro publication, google for AN296089 (I can't seem to get a link out of google) -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Possible lathe spindle encoder.
On 29 July 2015 at 19:42, Jerry Scharf wrote: The "dual channel" is the independent output of the two hall effect > transducers (available only in the surface mount part.) The other two > outputs are direction (simple binary pin) and speed. Speed is the XOR of > the two transducers, so it produces a full square wave for each magnet pass > under the device. You can then either time between edges of the square wave > to get an instantaeous angular velocity or between square waves to get the > rotation rate. Way easier that looking for a missing pulse. > Most LinuxCNC applications (especially a lathe spindle) need an index pulse. Car engines need an index pulse too, but they do that by having a missing tooth. (traditionally it was a shorter tooth on the starter ring-gear). 26.5 is absolute max voltage. The normal working range is 5 to 24V, so it will work in just about any automotive application. -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Possible lathe spindle encoder.
Andy, I read the datasheet and it looks really easy. The "dual channel" is the independent output of the two hall effect transducers (available only in the surface mount part.) The other two outputs are direction (simple binary pin) and speed. Speed is the XOR of the two transducers, so it produces a full square wave for each magnet pass under the device. You can then either time between edges of the square wave to get an instantaeous angular velocity or between square waves to get the rotation rate. Way easier that looking for a missing pulse. at $2.50 each, this is a cool part. The weird thing is the 26.5V supply voltage (clearly made for one customer...). That means an extra power supply and level converters on the outputs. It would be nicer if there was a 5V part (I didn't look for one.) Given that it's built for automotive, it is as close to indestructable as you can easily get for an electronics part. jerry On Wed, Jul 29, 2015 at 10:45 AM, andy pugh wrote: > On 29 July 2015 at 18:41, andy pugh wrote: > > > > > I can't find a source for the sensor in the US. > >> > > > > I think this is the one: > > http://www.digikey.com/product-detail/en/A1233LK-T/620-1487-ND/3878417 > > > > > Actually, that's a 2-channel one, rather than the 1-channel. I don't know > how you would detect the index (the car encoders have a missing-tooth > index) > > -- > atp > If you can't fix it, you don't own it. > http://www.ifixit.com/Manifesto > > -- > ___ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > -- Jerry Scharf FINsix IT 650.285.6361 w 650.279.7017 m -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Possible lathe spindle encoder.
On 29 July 2015 at 18:41, andy pugh wrote: > > I can't find a source for the sensor in the US. >> > > I think this is the one: > http://www.digikey.com/product-detail/en/A1233LK-T/620-1487-ND/3878417 > > Actually, that's a 2-channel one, rather than the 1-channel. I don't know how you would detect the index (the car encoders have a missing-tooth index) -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Possible lathe spindle encoder.
On 29 July 2015 at 18:32, Dave Cole wrote: > Does Ford buy them via Amazon ?? ;-) The price is right. > > http://www.amazon.co.uk/Febi-36070-Crankshaft-Timing-Wheel/dp/B00CD3DHXO > > I can't find a source for the sensor in the US. > I think this is the one: http://www.digikey.com/product-detail/en/A1233LK-T/620-1487-ND/3878417 -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Possible lathe spindle encoder.
Does Ford buy them via Amazon ?? ;-) The price is right. http://www.amazon.co.uk/Febi-36070-Crankshaft-Timing-Wheel/dp/B00CD3DHXO I can't find a source for the sensor in the US. Dave On 7/28/2015 6:01 AM, andy pugh wrote: > Now that many cars have automatic stop/start there is a requirement > for bidirectional crank position sensors. (So that the PCM can track > crank position if the crank rocks-back and still fire on the first > TDC). > > The sensors are (often) a magnetic track on the outside of a wheel. > The ones I have here a central boss with a 30mm bore, but this is > pressed into a sensor ring with a 70mm bore, which would be adequate > for quite large spindles. > > A typical encoder ring is Ford part number 7M5Q-6B319-BA which costs > £50 inclusive of VAT. > > The sensor is DS7Q-9E731-BA and costs £23 > > The encoder protocol is a bit unusual. Index is indicated by a missing > pulse, and direction is indicated by pulse length. So some changes > would be needed to the encoder component to support this class of > device. On the plus side you get index and direction for only one IO > line. > > I don't actually know what sensor is the Ford package however I have > found a direction-detecting sensor for ferrous targets such as gear > wheels here: > http://www.allegromicro.com/~/media/Files/Datasheets/ATS693-Datasheet.ashx?la=en > It isn't clear if that one can use missing-tooth index, it looks like > it might reject it as a vibration artefact. > > --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
