----- Original Message ----- From: "mvm" amvm@skynet.be To: "George Burr" gaburr@magma.ca; amsat-bb@amsat.org Sent: Wednesday, September 17, 2008 4:05 PM Subject: [amsat-bb] Re: rotor replacement pots
Has anybody tried to use other methods of sensing than the pots? I'm currently trying an electronic compass. First results are promising.
Eventually I want to completely replace the Yaesu controller.
BR,
//\arc ON4AMV
Hi George, ON4AMV
It is possible to use commercially available absolute encoders with linear analog output from 0 to 5 volt or from 0 to 10 volt for a single revolution of 360°
The above absolute encoders are more accurate than any conventional linear 360° potentiometer and they don't use moving contacts like a wiper built into a wirewound potentiometer.
They are made by Tekel, Eltra, Lika Electronic and many others manufacturers for robotics and industrial application but they are very expensive.
In addition the backlash into the gears of a G5400 rotator do not justify such high accuracy and a good wirewound linear 500 ohm potentiometer represents the best technical and economical solution.
By the way when a very high repeatedly position accuracy is requested as for large EME dishes then absolute encoders or resolvers with the associated syncro to digital converters are necessary.
73" de
i8CVS Domenico