Analog Encoders 1Vpp to 20Vpp?

[Zathras]

Hi people,

I have some Renishaw analog encoders ( RGH22A15L00 ) that have 1Vpp differential output and need to interface it with my Dynomotion KFlop+Kanalog controller board with 20Vpp differential input.
The "obvious" solution would be some amplifier but I can't seem to find anything.
Surely this would be a common problem?
Alternatively an ADC board could be possible to interface it with the dynomotion. Could anyone point me these interface boards or ICs?
I've already asked the Dynomotion forum but didn't really get any solution.

Thanks!

[Al_The_Man]

AFAIK Kanalog takes standard 5v RS422 differential input for encoders.
This may work, I have no personal experience with it though.
Deva Sinewave Interpolator
Doesn't look cheap though!
Al.

[Zathras]

Thanks Al.

The Kanalog also has analog inputs with ADCs that can be used with encoders.
It's just that the voltage range is -+ 10v not -+0.5v. I will lose too much resolution IMHO.
The Deva stuff is an alternative but definitely looking for a cheaper solution.
I'm pretty sure I found an IC that did just this last year but cannot remember how I found it. It seemed like a rather small ic company.

[Zathras]

Aha!

I think now I found it again, "IC-Haus"
Encoder products here;
iC-Haus Homepage - keyword: Encoder iCs

Still nothing to interface 1vpp to 20vpp but intersting ics here.

[TomKerekes]

The Kanalog also has analog inputs with ADCs that can be used with encoders.
It's just that the voltage range is -+ 10v not -+0.5v. I will lose too much resolution IMHO.

You might try it. +/-0.5V provides ~ +/- 100ADC counts. So theoretically +/- 1/2 count would be +/- 1/200th of a cycle. If the Scale pitch is 20um that would me 0.1um.

Someone recently interfaced an encode with 11uA pp output to Kanalog. There was a discussion on the Dynomotion yahoo group. We tried to just connect it directly but there were problems so he finally built an external amplifier.

Regards

[mike_Kilroy]

wow. weird how stuff works in this world sometimes......

I just had to build a 4 channel (for 2 feedback devices) amplifier board for a project that takes 4Vpp and outputs 20Vpp! worked great on this machine tool! Mine was for dual resolvers but the sine outputs are identical to the sine outputs of a 1Vpp encoder....

so if u r into building a small 1pc 50 cent op amp pcb with 8pc 2 cent resistors on it and 2 small adjustment pots, I will send u schematic. I used a 50k pot for gain adjustment of 0-5x; so u would just replace it with a 250k pot for 1V->20V = 20x gain. requires +/-15vdc supply in order to get 20Vpp output.