Thanks for the good information Domenico, that difference in dimensions is important because of the fine teeth on the gear. I also have an old Kenpro pot (somewhere)!!
73 Geo. Amsat# 26245
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
George Burr schreef:
Thanks for the good information Domenico, that difference in dimensions is important because of the fine teeth on the gear. I also have an old Kenpro pot (somewhere)!!
73 Geo. Amsat# 26245
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----- 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
Hi Domenico & George, Hi all,
another cheap solution is the AS 5040, however the SSOP-16 package of this IC is a problem for homebrewers, as the chip is very tiny and always needs a good PCB with high accuracy between the tracks. In addition is necessary to make some mechanical construction in order to support the moving-magnet and the circuit, in place of the old-conventional pot.
This IC working with digital -or- analogue output if you want a standalone device (0-5Volts for 0-360 degrees or by using a divider : 0-3.6 Volts for a direct digital readout).
A few nice examples you can find here:
http://www.electric-web.org/rotary_encoder.htm
http://vk5dj.mountgambier.org/Beam/AS5040/AS5040-45.html
However I completely agree with Domenico, the classical wire pot is the best techical and economical solution for Satellites. All the rest are much more complicated, and they need dozen-hours of experimentation. OK, even if the pot needs replacement from time to time, for me remains that a simple, easy and comfortable solution for our applications. And keep in mind, the POT is a "passive" component in contrast with any IC into the rotor, which is an active circuit into a non-friendly environment, like that inside of metal case of rotor, where extreme temperature take place between -35 on N.Europe, Canada etc and upto 80-90 Celsius on South areas !.
No very comfortable environment's condition for an IC - even if has a low power consumption.
73, Mak SV1BSX
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
Hi Domenico & George, Hi all,
another cheap solution is the AS 5040, however the SSOP-16 package of this IC is a problem for homebrewers, as the chip is very tiny and always needs a good PCB with high accuracy between the tracks. In addition is necessary to make some mechanical construction in order to support the moving-magnet and the circuit, in place of the old-conventional pot.
This IC working with digital -or- analogue output if you want a standalone device (0-5Volts for 0-360 degrees or by using a divider : 0-3.6 Volts for a direct digital readout).
A few nice examples you can find here:
http://www.electric-web.org/rotary_encoder.htm
http://vk5dj.mountgambier.org/Beam/AS5040/AS5040-45.html
However I completely agree with Domenico, the classical wire pot is the best techical and economical solution for Satellites. All the rest are much more complicated, and they need dozen-hours of experimentation. OK, even if the pot needs replacement from time to time, for me remains that a simple, easy and comfortable solution for our applications. And keep in mind, the POT is a "passive" component in contrast with any IC into the rotor, which is an active circuit into a non-friendly environment, like that inside of metal case of rotor, where extreme temperature take place between -35 on N.Europe, Canada etc and upto 80-90 Celsius on South areas !.
No very comfortable environment's condition for an IC - even if has a low power consumption.
73, Mak SV1BSX
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
participants (4)
-
George Burr -
i8cvs -
mvm -
SV1BSX