Re: [CAD_CAM_EDM_DRO] Looking for scale interprolator circut

You could also use an Atmel AT90mega8535 microcontroller. It has 8
channel 10 bit ADC, PWM output, etc. It can also be reprogrammed in
circuit. C, BASIC, Assembly and probably other languages are available.
http://tinyurl.com/aqm57
They're also quite cheap, $5.70 from Digi-Key.
http://tinyurl.com/ay4l2

Regards,
JJ

On 12-Sep-2005, at 19:28, Mcginnis, Darrell S wrote:

> It appeared that the manual had all the theory of operation that one
> would need to conceptually construct an interpolator from linear
> (sine/Cosine) scales.
>
> The implementation inferred is to digitize sine and cosine, then
> multiply them together(read the part that mentions arctan) yielding a
> larger numeric range than just the digitizing allows. Implementation
> must throw away enough numeric noise to ensure not dropping steps on
> reasonable inputs. (or provide means to produce extra steps when a
> missing step is noticed.)
>
> A discrete HW implementations could be:
> use two ADC 8 bit converters to generate a 16 bit address to a ROM;
> Program the ROM to output an absolute rotational position (based on
> arctan, like 16 bits wide?)
> Have an up/down counter increment or decrement to track the absolute
> position from the rom (ROM data and counter feed a comparator that
> indicates inc/dec/nop). QUadrature is generated from up/down count
> events.... (width of the ROM and up/down counter should match; and
> number of unique rotational positions the ROM is programmed with
> dictates how much interpolation is done)
>
> Added logic probably needs to handle wrap conditions.
> One could through away the tracking counter if inputs are clean enough
> and/or you through away some precision and avoid possibility of missed
> steps...
>
> Depending on speed of ADC and a cpu, the algorithm can be SW...
>
>
>
> -----Original Message-----
> From: CAD_CAM_EDM_DRO@yahoogroups.com
> [mailto:CAD_CAM_EDM_DRO@yahoogroups.com] On Behalf Of th.carel
> Sent: Thursday, September 08, 2005 6:18 AM
> To: CAD_CAM_EDM_DRO@yahoogroups.com
> Subject: Re: [CAD_CAM_EDM_DRO] Looking for scale interprolator circut
>
> Trevor
>
> Not a great cheap issue , sorry , I had the same problem
> with 2 glass linear scales from heidenhain + the need for
> an extra Z.
> I found a used Metrologic DRO wich work with sinus scales
> and send the data through the RS232 to the pc (configured as terminal)
> Metrologic today ,are more interested with the laser barecode devices
> ,and
> it could be an idea to contact and ask for an "old" used unit sinus
> compatible ?
> (CMM =MMT in french)
> Check for Metrologic group , MMT and directly to a technician.
> They send me the connectors data , the setting , and the protocole
> description !
> (a setting for signal multiplier is included)
>
> 2/check Ebay for a heidenhain dro , more common ,(I found my Z for
> 220
> Euros.)
>
> 3/Heidehain provide also some converting magic box (Ebay ?)
>
> 4/ checking the sinus dro input (for to act as you) , I found the trick
> but
> ,to
> cut all the analogic input part ,shorting the hooking and connect
> directly
> to
> the appropriate CI pins was too tiedous (but possible !)
>
> I suspect (maybe I'm wrong) you plan to hook your sin rulers to Mach2/3
> ,
> as me , I suggest an other issue , keep your rulers as original and
> through
> a dro interface , send the datas when the rs232 input protocole will be
> fully enabled ..?
>
> thierry
>
>
> ----- Original Message -----
> From: "protman16" <protman16@...>
> To: <CAD_CAM_EDM_DRO@yahoogroups.com>
> Sent: Tuesday, September 06, 2005 7:54 PM
> Subject: [CAD_CAM_EDM_DRO] Looking for scale interprolator circut
>
>
>> Group,
>>
>> Does anyone have information where I can find an interpolation
>> circuit
>> for converting a sine-cosine linear scale signal to square wave
>> quadrature signal?
>> Ideally the circuit would also have selectable multiplier for the
>> output.
>>
>> Trevor
>>
>>
>>
>>
>>
>>
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> URL to this group: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO
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> OFF Topic POSTS: General Machining
> If you wish to post on unlimited OT subjects goto:
> aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach
> it
> if you have trouble.
> http://www.metalworking.com/news_servers.html
>
> http://groups.yahoo.com/group/jobshophomeshop I consider this to be a
> sister site to the CCED group, as many of the same members are there,
> for OT subjects, that are not allowed on the CCED list.
>
> NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING
> THEM.
> DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........
> bill
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> [Moderators]
> URL to this group: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO
>
> OFF Topic POSTS: General Machining
> If you wish to post on unlimited OT subjects goto:
> aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach
> it if you have trouble.
> http://www.metalworking.com/news_servers.html
>
> http://groups.yahoo.com/group/jobshophomeshop I consider this to be
> a sister site to the CCED group, as many of the same members are
> there, for OT subjects, that are not allowed on the CCED list.
>
> NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING
> THEM. DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........
> bill
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