I’ve just posted an article about the Omni-E Faceting Machine’s digital encoder.
I finally got the time and energy to take apart the Omni’s faceting head and encoder and snap some pictures. What did I discover? Nothing that I wasn’t expecting, really.
The Omni-E’s greatest marketing hype has been that it’s a “true digital” faceting machine because it utilizes a digital optical encoder to measure the angle of the faceting head. Most of the competition in the digital faceting head world – Polymetric, Graves Mk 5 (and of course its parent the XS3, which is no longer being manufactured) – use high-tolerance potentiometers to measure the faceting head angle. Though they are digital angle read-outs, the argument has been that using an analog pot to measure the angle is somehow less accurate or inferior to a digital encoder.
You can read the article to discover the truth. The Omni-E I have uses a US Digital E5 Optical Encoder that resolves to 900 counts per revolution. It effectively can measure up to 3600 divisions per revolution by reading the outputs in a specific way. Which means the Omni-E can resolve at best to 0.1 degrees, plus or minus whatever the error is in the encoder. However at least one of the potentiometer-based competitors can repeatably and accurately resolve to 0.02 degrees, five times greater resolution than the Omni’s digital encoder!
Click on this link to read about the Omni-E Faceting Machine’s digital encoder.