Reply with QuoteNot only wrong about quadrature but also the number of tracks, its possible to use two tracks but itsOriginally Posted by Al_The_Man
normally a bad way to do it, Normal quadrature encoders use a single track and offset detectors/ Ronchi gratings
Wrong Dissemination of terms.
I was perusing a few sites today and was surprised that so many offer the wrong source of the definition for a Quadrature Encoder.
The offenders all gave a variation of below. Many that should know better.!!
e,g:
"The name quadrature comes from the. four possible output states of the encoder sensor
Rather than just a single pulse indicating a slotted or striped track in a codewheel, quad encoders use a pair of tracks to go through four distinct phases. . .quad means four."
Simply not true.
The original meaning of the term Quadrature in this context meant that the two waveform's are displaced by 90°.
In fact the early Quadrature encoder simply used the two A & B signals and did not use the x4 method.
Another example of wrong dissemination of information/terminology.
Al.
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CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
Re: Wrong Dissemination of terms.
Not only wrong about quadrature but also the number of tracks, its possible to use two tracks but its
normally a bad way to do it, Normal quadrature encoders use a single track and offset detectors/ Ronchi gratings
Re: Wrong Dissemination of terms.
The first quadrature scales I was involved in used a incandescent lamp for the reading head, they use just the two A/B pulses, one for resolution, the other for direction.
The reading of high resolution gratings is still done by the using the Moiré effect, effectively enlarging the grating resolution many times.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
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