Pete C. wrote:


The idea that after missing some pulses the resolver will recover
absolute position eventually is pretty useless in this application,
since you have something like a 90:1 drive ratio to the table, and
knowing the motor is at position X tells you nothing about the position
of the RT. If you loose pulses your RT will remain off until you re-home
it. You should also not have any noise issues if you use shielded
cables, and ideally differential line drivers and receivers.

Actually, if noise has caused some error in the solution of the equation
and then the noise abates, the resolver converter WILL correct the error
and produce sufficient quadrature counts to get the computer back to the
exact correct encoder count. Now, if the computer has counted invalid
encoder counts due to electrical noise, that will not be corrected, but
it is the same situation as noise on traditional encoder circuits. I
don't see the difference there. Since Iggy will be putting a
differential-out resolver converter in the same cabinet as the
differential-input encoder counter, the chance of counting errors
between them is extremely unlikely.

The only way the resolver converter will permanently mess up is if the
noise is so great that it starts reading 180 degrees out of sync with
the resolver. Then when the noise clears up, it could correct position
going around the wrong way, or have lost entire revolutions of the
resolver. In this case, the noise problem must be corrected.

The resolver provides a unique reading at any rotation, and the
converter tracks that position. It does not produce "pulses" and
therefore cannot "miss some pulses".

Jon