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What's new

Can anyone give a "Chalk Talk" on the theory underlying Spherosyn scale and encoder operation?

Is it possible the Spherosyn sensors work like a vernier? That is, say the balls are 6 mm diameter, and the reader has a pair of pickups that read maximum over a ball (or the low spot between balls), and the sensors are 5.999 mm apart? There would need to be two pairs of sensors to allow quadrature sensing of direction. This is my SWAG. (Quadrature means having a pair of signals 90 degrees out of phase.)
I think there is a good chance they may have sort of "Magic" in their configuration. One detailed diagram of their coil system showed 4pairs of driver/pickup coils. That would allow various summing and subtraction options to improve signal precision.

If anyone has a "dead"encoder it would be very interesting to do an autopsy on it.

Denis
 
Absolutely fascinating, I knew nothing about these things so +1 on learning a new thing, it occurs that a circular tube could be a rotary encoder or am ( as usual) mistaken? It would be fairly insensitive to heat say.
Mark
The one thing against a circular tube arrangement is that the balls are loaded into straight tubes and then spring loaded to keep them snuggly in place. It might be a bit challenging to load the balls and then close the circular tube AND have the balls tightly packed. Theory does not seem to allow a spring or some other compliant spacer in the circular ball array as that would be a "dead" spot in the tube.

I fully agree with the learning a new thing idea.

Denis
 
A relevant patent is US6977594, available from Google Patents.

The original idea was patented in 1973, according to Newall. I don't have the reference at hand.

Newall publishes a tutorial: "Linear Encoder Technology - A Guide To Understanding Newall's Spherosyn & Microsyn Linear Feedback Encoders".
 
A relevant patent is US6977594, available from Google Patents.

The original idea was patented in 1973, according to Newall. I don't have the reference at hand.

Newall publishes a tutorial: "Linear Encoder Technology - A Guide To Understanding Newall's Spherosyn & Microsyn Linear Feedback Encoders".
So, I searched on that title and here is the link that provides a very good “chalk talk,” indeed.

The nitty gritty

Thank you!!

Denis
 
Did you have a Microsyn or Spherosyn scale on the X? I had a Turnmaster clone of a 17" X 80 Colchester, had a Topaz DRO on it with a microsyn on the X. I didn't have that issue. Most DROs have the ability to internally correct for that if it arises, I'd imagine Newalls do too.
I had both. Replaced the Spherosyn with a Microsyn on x Per the dealer’s recommendation. Better, but still not as linear as I would have liked. I got rid of it when the z cable failed. Nobody said anything about internal correction.
 
Nobody said anything about internal correction.
I'm only surmising that newall had it, apparently not. Part of the setup procedure on the Accurite turnvision I have on my current manual lathe is testing it with micrometer standards or gage blocks and a test indicator and entering correction values in the box.
 
I'm only surmising that newall had it, apparently not. Part of the setup procedure on the Accurite turnvision I have on my current manual lathe is testing it with micrometer standards or gage blocks and a test indicator and entering correction values in the box.
it might be that the Newall unit you had did not have error compensation. However, their current units do. Here are a couple of snips of the installation manual for the DP1200.
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Denis
 








 
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