On Fri, Nov 23, 2012 at 11:21 AM, andy pugh bodge...@gmail.com 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
On 27 November 2012 20:21, Przemek Klosowski
przemek.klosow...@gmail.com 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.
andy pugh wrote:
On 27 November 2012 20:21, Przemek Klosowski
przemek.klosow...@gmail.com 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
well gene i agree the mopar sensor is junk but these are 19 bucks like i said :)
http://compare.ebay.com/like/181031267122?var=lvltyp=AllFixedPriceItemTypesvar=sbar
On Sat, Nov 24, 2012 at 12:49 AM, Gene Heskett ghesk...@wdtv.com wrote:
On Saturday 24 November 2012 00:38:21 jeremy youngs did
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
:)
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=lvltyp=AllFixedPriceItem
Typesvar=sbar
So mopar is as usual, ripping people off. And have been doing
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 comparator
On 23 November 2012 04:04, Gene Heskett ghesk...@wdtv.com 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
On Friday 23 November 2012 09:14:56 andy pugh did opine:
On 23 November 2012 04:04, Gene Heskett ghesk...@wdtv.com 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
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 ghesk...@wdtv.com wrote:
On Friday 23 November 2012 09:14:56 andy pugh did
On 23 November 2012 14:26, Gene Heskett ghesk...@wdtv.com 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
On 23 November 2012 15:22, Stuart Stevenson stus...@gmail.com 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
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
--
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
transmissions , differentials and wheels are not :)
On Fri, Nov 23, 2012 at 11:09 AM, Dave Caroline
dave.thearchiv...@gmail.com 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
On 23 November 2012 16:09, Dave Caroline dave.thearchiv...@gmail.com 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
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
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 bodge...@gmail.com wrote:
On 23
On Fri, Nov 23, 2012 at 4:21 PM, andy pugh bodge...@gmail.com wrote:
On 23 November 2012 16:09, Dave Caroline dave.thearchiv...@gmail.com 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
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
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
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
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
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
On Saturday 24 November 2012 00:21:24 andy pugh did opine:
On 23 November 2012 14:26, Gene Heskett ghesk...@wdtv.com 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
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 point
On 22 November 2012 02:32, Gene Heskett ghesk...@wdtv.com 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,
On 22 November 2012 11:26, Dave Caroline dave.thearchiv...@gmail.com 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.
On 11/22/2012 6:42 AM, andy pugh wrote:
On 22 November 2012 11:26, Dave Carolinedave.thearchiv...@gmail.com 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
On Thursday 22 November 2012 09:59:53 andy pugh did opine:
On 22 November 2012 11:26, Dave Caroline dave.thearchiv...@gmail.com
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.
On 22 November 2012 15:36, Gene Heskett ghesk...@wdtv.com 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
On 22 November 2012 14:55, Dave e...@dc9.tzo.com 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
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 bodge...@gmail.com wrote:
On 22 November 2012 14:55, Dave e...@dc9.tzo.com wrote:
How does the car controls handle the possible partial reverse rotation
of the
On 22 November 2012 16:11, jeremy youngs jcyoung...@gmail.com 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
andy pugh wrote:
On 22 November 2012 11:26, Dave Caroline dave.thearchiv...@gmail.com 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
On 22 November 2012 20:51, Jon Elson el...@pico-systems.com 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
On Thursday 22 November 2012 23:03:13 andy pugh did opine:
On 22 November 2012 20:51, Jon Elson el...@pico-systems.com 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
andy pugh wrote:
On 22 November 2012 20:51, Jon Elson el...@pico-systems.com 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
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,
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
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
On 21 November 2012 22:57, Gene Heskett ghesk...@wdtv.com 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
On Wednesday 21 November 2012 18:41:41 andy pugh did opine:
On 21 November 2012 22:57, Gene Heskett ghesk...@wdtv.com 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
On Wednesday 21 November 2012 21:30:14 andy pugh did opine:
On 21 November 2012 23:53, Gene Heskett ghesk...@wdtv.com 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.
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 intended
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, a
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