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Author Topic: Converting Heidenhain sine wave to TTL  (Read 15845 times)

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Converting Heidenhain sine wave to TTL
« on: February 21, 2012, 06:38:03 PM »
Hello everybody
I have scored an Heidenhain glass scale,i would like to run with Mach3, the scale puts out a sine wave, but Mach3 only handles TTL signals.
Have anyone made a working Schmitt trigger for this, and are you willing to share the schematics. I am able to read schematics, make PCB's and solder, but i can't figure it out if you only says "just use part no. ********* and it will work"
Hope somebody are able to help.

Holt
Re: Converting Heidenhain sine wave to TTL
« Reply #1 on: February 22, 2012, 02:19:20 PM »
To show you what i got to work with, this is a scan of the Heidenhain manual



What i need is a signal looking like this



Any help much appreciated

Holt
Re: Converting Heidenhain sine wave to TTL
« Reply #2 on: February 22, 2012, 04:40:41 PM »
What you need goes FAR beyond simply using a Schmitt trigger to convert the sine wave to TTL.  What you have is an anlog resolver, which will output one cycle of sine wave for each full revolution of the resolver.  To get useful position information from that, you need to do an a very precise analog to digital conversion.  You'd be far better off replacing those with digital encoders.

Regards,
Ray L.
Regards,
Ray L.
Re: Converting Heidenhain sine wave to TTL
« Reply #3 on: February 23, 2012, 12:11:42 AM »
Thanks Ray
I wont replace the scale, one scale costs as much as my entire lathe!
 If i can't build anything myself, i will be watching the bay for a cheap Heidenhain interpolation box

Re: Converting Heidenhain sine wave to TTL
« Reply #4 on: February 23, 2012, 12:25:45 AM »
You can buy a good digital encoder for under $30....
Regards,
Ray L.
Re: Converting Heidenhain sine wave to TTL
« Reply #5 on: February 23, 2012, 02:43:14 AM »
You can buy a good digital encoder for under $30....

Could you suggest any

Holt
Re: Converting Heidenhain sine wave to TTL
« Reply #6 on: February 26, 2012, 02:54:22 PM »
I just got a Heidenhain EXE 610 C interpolation box on ebay Germany for 12.50 Eur, no need to warm up the solder iron then  :D
Re: Converting Heidenhain sine wave to TTL
« Reply #7 on: February 26, 2012, 03:12:06 PM »
You can buy a good digital encoder for under $30....

Could you suggest any

Holt

These are the ones I use - about US$23 each:

http://products.cui.com/CUI_AMT102-V_Datasheet.pdf?fileID=7573

Regards,
Ray L.
Regards,
Ray L.

Offline Dan13

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Re: Converting Heidenhain sine wave to TTL
« Reply #8 on: February 27, 2012, 06:24:42 AM »
For what it's worth, it's not a resolver. It's rather a variation of a Sine quadrature encoder. It's implemented on a scale rather than on a rotary encoder. The sine/cosine signals are decoded in the Heidenhain controller with a AD converter of some resolution. For instance an 8-bit converter will break the sine wave into 256 parts and thus it will get a resolution multiplied by that amount compared to the scale resolution.

Considering the above, while you would be able to use a simple Schmitt trigger to produce digital quadrature signals from the sine/cosine ones, you would lose resolution to such an extent making the scale not efficient. A further electronic gearing circuit could be added, but that would make things much more complicated.

Dan
Re: Converting Heidenhain sine wave to TTL
« Reply #9 on: February 27, 2012, 03:07:04 PM »
As a point of interest, all optical encoders and scales of this type, TTL included,  start off with an optically detected signal that  is sine wave in nature, in a TTL Incremental quadrature encoder type, the sine wave is squared up and converted to TTL and/or Differential output.
In these Heidenhain and similar scales or encoders, the arc tangent function is used to produce a high resolution absolute encoder count from the sine/cosine signal.
As suggested, you could use an op amp to amplify this signal and square it up and produce a TTL quadrature signal.
Nosmo.
  
 
« Last Edit: February 27, 2012, 03:15:03 PM by NosmoKing »