Re: [Emc-users] Spindle position, direction and Index with only one channel.

andy pugh wrote: > On 27 November 2012 20:21, Przemek Klosowski > wrote: > > >> OK, but there's very little consequence if the engine controls get it >> wrong, correct? it'd just keep turning over and fire on another TDC. >> Whereas rigid tapping would go quite wrong if it was off by a revoluti

Re: [Emc-users] Spindle position, direction and Index with only one channel.

On 27 November 2012 20:21, Przemek Klosowski wrote: > OK, but there's very little consequence if the engine controls get it > wrong, correct? it'd just keep turning over and fire on another TDC. > Whereas rigid tapping would go quite wrong if it was off by a revolution. No, as long as it is exac

Re: [Emc-users] Spindle position, direction and Index with only one channel.

On Fri, Nov 23, 2012 at 11:21 AM, andy pugh wrote: > > The bidirectional sensors are for start-stop applications where it is > important to retain crank-synch even during rock-back when the engine > stops. > We need to inject fuel on the very first available TDC to meet the > start-time targets.

Re: [Emc-users] Spindle position, direction and Index with only one channel.

On Saturday 24 November 2012 21:05:58 James Boulton did opine: > Has anyone on list used a stepper as an encoder like this: > > http://home.clear.net.nz/pages/joecolquitt/stepper_as_encoder.html > > James I breadboarded a similar circuit, feeding the coils of a small 24v stepper into a compara

Re: [Emc-users] Spindle position, direction and Index with only one channel.

On Saturday 24 November 2012 20:39:45 jeremy youngs did opine: > well gene i agree the mopar sensor is junk but these are 19 bucks like i > said :) > http://compare.ebay.com/like/181031267122?var=lv Types&var=sbar So mopar is as usual, ripping people off. And have been doi

Re: [Emc-users] Spindle position, direction and Index with only one channel.

Has anyone on list used a stepper as an encoder like this: http://home.clear.net.nz/pages/joecolquitt/stepper_as_encoder.html James On Sat, 2012-11-24 at 19:01 -0500, jeremy youngs wrote: > well gene i agree the mopar sensor is junk but these are 19 bucks like i said > :) > http://compare.ebay.

Re: [Emc-users] Spindle position, direction and Index with only one channel.

well gene i agree the mopar sensor is junk but these are 19 bucks like i said :) http://compare.ebay.com/like/181031267122?var=lv On Saturday 24 November 2012 00:38:21 jeremy youngs did opine: > >> actuall

Re: [Emc-users] Spindle position, direction and Index with only one channel.

On Saturday 24 November 2012 00:38:21 jeremy youngs did opine: > actually accuracy is needed as it has to pick up thta position on fire > up :) it is also to note that several reversible sensors of identical > or similar design are found everywhere on autos. this is not a > dissertation just poin

Re: [Emc-users] Spindle position, direction and Index with only one channel.

On Saturday 24 November 2012 00:21:24 andy pugh did opine: > On 23 November 2012 14:26, Gene Heskett wrote: > >> The target wheels we have on our engines are _not_ ferrous. They are > >> a magnetic track and the crank sensor has no internal magnet. > >> (I can't find that actual sensor on the All

Re: [Emc-users] Spindle position, direction and Index with only one channel.

as to the autos variable reluctance is cheap and effective for things that arent too slow as voltage is a function of rpm in them . Hall effects require magnets and collect debris (as does variable reluctance) and are not as robust in my experience. Led/ collector is a fairly robust system with goo

Re: [Emc-users] Spindle position, direction and Index with only one channel.

Interestingly, this sort of sensor would have been helpful on my latest problem with the lathe spindle Z pulse encoder I wanted to run on a pulley at 3x the spindle rate, presuming there was software support for it. In my case the pulse length accounting would have had to have been in the 7i33 fir

Re: [Emc-users] Spindle position, direction and Index with only one channel.

Sounds like this could be a major move forward. I'm not wed to the full quadrature concept. This sounds like it is almost an absolute encoder? Or close? I've got to get back to working on an SSI absolute encoder interface now that I am back home. Julian was working on a SSI interface on the

Re: [Emc-users] Spindle position, direction and Index with only one channel.

Stuart Stevenson wrote: > Seems to me a resolver would be the best choice for position on start up. > Velocity could be derived also. A resolver on the cam and crank could tell > you the next piston to reach tdc You check the price on a resolver, lately? The problem is a wound-rotor brushless res

Re: [Emc-users] Spindle position, direction and Index with only one channel.

actually accuracy is needed as it has to pick up thta position on fire up :) it is also to note that several reversible sensors of identical or similar design are found everywhere on autos. this is not a dissertation just point to the larger world. i think andy is trying to feel whether we are int

Re: [Emc-users] Spindle position, direction and Index with only one channel.

On Fri, Nov 23, 2012 at 4:21 PM, andy pugh wrote: > On 23 November 2012 16:09, Dave Caroline wrote: >> Car engines are unidirectional Unless you fit a Bolinder or other boat engine >> >> The reverse detection is probably only an error signal > > I thought I explained this already? The error I ta

Re: [Emc-users] Spindle position, direction and Index with only one channel.

you did i was just saying that there are many similar systems requiring racking and a carte blanche statement would not apply :) nor the "probably" an error statement which is pure speculation not based in experience On Fri, Nov 23, 2012 at 11:21 AM, andy pugh wrote: > On 23 November 2012 16:09,

Re: [Emc-users] Spindle position, direction and Index with only one channel.

I, too, find this thread interesting. -- dos centavos -- Monitor your physical, virtual and cloud infrastructure from a single web console. Get in-depth insight into apps, servers, databases, vmware, SAP, cloud infrastruc

Re: [Emc-users] Spindle position, direction and Index with only one channel.

On 23 November 2012 16:09, Dave Caroline wrote: > Car engines are unidirectional Unless you fit a Bolinder or other boat engine > > The reverse detection is probably only an error signal I thought I explained this already? The bidirectional sensors are for start-stop applications where it is imp

Re: [Emc-users] Spindle position, direction and Index with only one channel.

transmissions , differentials and wheels are not :) On Fri, Nov 23, 2012 at 11:09 AM, Dave Caroline wrote: > Car engines are unidirectional Unless you fit a Bolinder or other boat engine > > The reverse detection is probably only an error signal > > Dave Caroline > > -

Re: [Emc-users] Spindle position, direction and Index with only one channel.

Car engines are unidirectional Unless you fit a Bolinder or other boat engine The reverse detection is probably only an error signal Dave Caroline -- Monitor your physical, virtual and cloud infrastructure from a single

Re: [Emc-users] Spindle position, direction and Index with only one channel.

not everyone andy :) 15 yrs as an auto tech im actually understanding of what you are trying to do. however i do not have an immediate application to justify your time :( but thanx for sharing. I have wondered why machines dont follow the same stategy as autos involving rotational positioning --

Re: [Emc-users] Spindle position, direction and Index with only one channel.

On 23 November 2012 15:22, Stuart Stevenson wrote: > Seems to me a resolver would be the best choice for position on start up. This is the car industry. Cost is everything. They probably use the one-wire sensor purely to save the extra wire and connectors that a quadrature sensor would need. If y

Re: [Emc-users] Spindle position, direction and Index with only one channel.

On 23 November 2012 14:26, Gene Heskett wrote: >> The target wheels we have on our engines are _not_ ferrous. They are a >> magnetic track and the crank sensor has no internal magnet. >> (I can't find that actual sensor on the Allegro site). > > For a hall sensor to work, there must be a magnetic

Re: [Emc-users] Spindle position, direction and Index with only one channel.

Seems to me a resolver would be the best choice for position on start up. Velocity could be derived also. A resolver on the cam and crank could tell you the next piston to reach tdc. On Nov 23, 2012 8:30 AM, "Gene Heskett" wrote: > On Friday 23 November 2012 09:14:56 andy pugh did opine: > > > On

Re: [Emc-users] Spindle position, direction and Index with only one channel.

On Friday 23 November 2012 09:14:56 andy pugh did opine: > On 23 November 2012 04:04, Gene Heskett wrote: > >> To buy the crank code-wheel new is not that cheap ($100) but there > >> ought to be many in the junkyards now. The correct pickups are less > >> likely to exist, but those are $17. > >

Re: [Emc-users] Spindle position, direction and Index with only one channel.

On 23 November 2012 04:04, Gene Heskett wrote: >> To buy the crank code-wheel new is not that cheap ($100) but there >> ought to be many in the junkyards now. The correct pickups are less >> likely to exist, but those are $17. > > Since the requirement is that its ferrous, I seen no reason that c

Re: [Emc-users] Spindle position, direction and Index with only one channel.

andy pugh wrote: > On 22 November 2012 20:51, Jon Elson wrote: > > >> Generally, I just don't see the advantage of going to a single >> sensor/single wire >> scheme when there are so many potential pitfalls. >> > > The single-wire is just a side-effect of using an encoder wheel that > is r

Re: [Emc-users] Spindle position, direction and Index with only one channel.

On Thursday 22 November 2012 23:03:13 andy pugh did opine: > On 22 November 2012 20:51, Jon Elson wrote: > > Generally, I just don't see the advantage of going to a single > > sensor/single wire > > scheme when there are so many potential pitfalls. > > The single-wire is just a side-effect of us

Re: [Emc-users] Spindle position, direction and Index with only one channel.

On 22 November 2012 20:51, Jon Elson wrote: > Generally, I just don't see the advantage of going to a single > sensor/single wire > scheme when there are so many potential pitfalls. The single-wire is just a side-effect of using an encoder wheel that is readily available and has a big centre bor

Re: [Emc-users] Spindle position, direction and Index with only one channel.

andy pugh wrote: > On 22 November 2012 11:26, Dave Caroline wrote: > > >> Current encoder inputs need 50% ratio >> Some cleaning/retiming required >> > > I can't decide if it is a special case of counter mode, or a whole new > component. > It actually gets fairly complicated! To handle

Re: [Emc-users] Spindle position, direction and Index with only one channel.

On 22 November 2012 16:11, jeremy youngs wrote: > or use a cam sensor, either way the controller will figure it in 2 > revolutions or less We currently have a requirement to fire on the second TDC (of a 4-cylinder) That's less than 180 crank degrees. -- atp If you can't fix it, you don't own it

Re: [Emc-users] Spindle position, direction and Index with only one channel.

or use a cam sensor, either way the controller will figure it in 2 revolutions or less On Thu, Nov 22, 2012 at 10:54 AM, andy pugh wrote: > On 22 November 2012 14:55, Dave wrote: > >> How does the car controls handle the possible partial reverse rotation >> of the engine when it stops? > > Tr

Re: [Emc-users] Spindle position, direction and Index with only one channel.

On 22 November 2012 14:55, Dave wrote: > How does the car controls handle the possible partial reverse rotation > of the engine when it stops? Tracking reverse rotation is the whole point of these direction-sensitive devices. Before stop-start the system would have to wait to see an index to fi

Re: [Emc-users] Spindle position, direction and Index with only one channel.

On 22 November 2012 15:36, Gene Heskett wrote: > In any event, it will need a separate index pulse, used to make sure there > have been no missing or extranious(sp) pulses since LinuxCNC tracks windup > with very wide counters. I am not sure this is necessarily true. LinuxCNC only typically _use

Re: [Emc-users] Spindle position, direction and Index with only one channel.

On Thursday 22 November 2012 09:59:53 andy pugh did opine: > On 22 November 2012 11:26, Dave Caroline wrote: > > Current encoder inputs need 50% ratio > > Some cleaning/retiming required > > I can't decide if it is a special case of counter mode, or a whole new > component. Because the pulse w

Re: [Emc-users] Spindle position, direction and Index with only one channel.

On 11/22/2012 6:42 AM, andy pugh wrote: > On 22 November 2012 11:26, Dave Caroline wrote: > > >> Current encoder inputs need 50% ratio >> Some cleaning/retiming required >> > I can't decide if it is a special case of counter mode, or a whole new > component. > > How does the car con

Re: [Emc-users] Spindle position, direction and Index with only one channel.

On 22 November 2012 11:26, Dave Caroline wrote: > Current encoder inputs need 50% ratio > Some cleaning/retiming required I can't decide if it is a special case of counter mode, or a whole new component. -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto ---

Re: [Emc-users] Spindle position, direction and Index with only one channel.

I only see one fly in the ointment Current encoder inputs need 50% ratio Some cleaning/retiming required Dave Caroline -- Monitor your physical, virtual and cloud infrastructure from a single web console. Get in-depth i

Re: [Emc-users] Spindle position, direction and Index with only one channel.

On 22 November 2012 02:32, Gene Heskett wrote: >> I think it makes sense to do index the same way as engines do, just >> have a short tooth so there is a pulse missing. >> > But, would that not upset any speed controls? The encoder counter would need to compensate. it isn't too hard, because the

Re: [Emc-users] Spindle position, direction and Index with only one channel.

Gene Heskett wrote: > A 100mm wheel is a bit large for my small lathe, but probably fine for the > 9" and up stuff, and if its quadrature direction sensing too, or 2 sensors > could be made so, then it sounds like something that would be a heck of a > lot less fuss to install & make work. IOW,

Re: [Emc-users] Spindle position, direction and Index with only one channel.

andy pugh wrote: > I have a rather interesting datasheet from Allegro. They have a sensor > that detects either a magneic codewheel, or a gear tooth (with a > biasing magnet behind the sensor). > The neat part is that the pulse width is 45uS in one direction, and > 90uS in the other. > It is intend

Re: [Emc-users] Spindle position, direction and Index with only one channel.

On Wednesday 21 November 2012 21:30:14 andy pugh did opine: > On 21 November 2012 23:53, Gene Heskett wrote: > > And I am thinking that an index for that could be obtained by drilling > > a 2 or 3mm hole in the added disk and setting a 2nd such device to > > sense the hole going by. > > I think

Re: [Emc-users] Spindle position, direction and Index with only one channel.

On 21 November 2012 23:53, Gene Heskett wrote: > And I am thinking that an index for that could be obtained by drilling a 2 > or 3mm hole in the added disk and setting a 2nd such device to sense the > hole going by. I think it makes sense to do index the same way as engines do, just have a short

Re: [Emc-users] Spindle position, direction and Index with only one channel.

On Wednesday 21 November 2012 18:41:41 andy pugh did opine: > On 21 November 2012 22:57, Gene Heskett wrote: > > Ahh, so. Do you have a link so we are on the same page with our > > thinking? > > http://www.allegromicro.com/en/Products/Magnetic-Speed-Sensor-ICs/Transm > ission-Sensor-ICs/ATS692.

Re: [Emc-users] Spindle position, direction and Index with only one channel.

On 21 November 2012 22:57, Gene Heskett wrote: > Ahh, so. Do you have a link so we are on the same page with our thinking? http://www.allegromicro.com/en/Products/Magnetic-Speed-Sensor-ICs/Transmission-Sensor-ICs/ATS692.aspx > Am I to understand that turning one way its a 90 degree duty cycle

Re: [Emc-users] Spindle position, direction and Index with only one channel.

On Wednesday 21 November 2012 17:49:39 andy pugh did opine: > On 21 November 2012 21:10, Gene Heskett wrote: > > A 100mm wheel is a bit large for my small lathe, but probably fine for > > the 9" and up stuff, and if its quadrature direction sensing too, or > > 2 sensors could be made so, then it

Re: [Emc-users] Spindle position, direction and Index with only one channel.

On 21 November 2012 21:10, Gene Heskett wrote: > A 100mm wheel is a bit large for my small lathe, but probably fine for the > 9" and up stuff, and if its quadrature direction sensing too, or 2 sensors > could be made so, then it sounds like something that would be a heck of a > lot less fuss to i

Re: [Emc-users] Spindle position, direction and Index with only one channel.

I have used these on a competition robot before. They were set up to detect sprocket teeth. Worked great until the mount got a little loose, then it got ground to dust (the magic smoke leaked out at that point). Ray --J. Ray Mitchell Jr. jrmitche...@gmail.com (818)324-7573 A foolish faith in au

Re: [Emc-users] Spindle position, direction and Index with only one channel.

On Wednesday 21 November 2012 16:05:50 andy pugh did opine: > I have a rather interesting datasheet from Allegro. They have a sensor > that detects either a magneic codewheel, or a gear tooth (with a > biasing magnet behind the sensor). > The neat part is that the pulse width is 45uS in one direct

[Emc-users] Spindle position, direction and Index with only one channel.

I have a rather interesting datasheet from Allegro. They have a sensor that detects either a magneic codewheel, or a gear tooth (with a biasing magnet behind the sensor). The neat part is that the pulse width is 45uS in one direction, and 90uS in the other. It is intended for crankshaft sensing, wh