Two rotary encoder questions

I have a number of HP rotary encoders. Some were stolen from the old
Goldmine motors, others from old HP Deskjet printers.

I have been spectacularly unsuccessful in removing the codewheels from
the mounts for either of these motors.

I wasn't too worried, though, as USDIgital's prices for codewheels is
quite affordable.

However, I am having trouble understanding exactly what I have here and am
unclear about which codewheels to order, fpr at least one of the encoders.


The HP Injet encoders are marked QEDS9557 or QEDS9500. They look exactly
like the more common HEDS encoders.

The codewheels are marked 504 and in quadrature produce 2000 counts. Makes
sense, I guess.

The optical diameter of the codewheel ( near as I can measure ) is 35 mm.


The Goldmine encoders are marked HEDS9100 with another marking of A00.

These codewheels are marked 1000 and produce 4000 counts in quadrature. Also
makes sense.

The optical diameter of these is 44 mm.


The HP HEDS datasheet "rates" encoders in CPR when used with codewheels
that have an optical diameter of 22 mm.

This is consistent with the Goldmine setup .. the 9100-A00 is rated as
500 CPR, the codewheel diameter is double the "reference" and so I get
twice the counts.

The Inkjet codewheel is a bit different, though. Its optical diameter is
very nearly 1.6 times the reference diameter of 22 mm. Am I correct in
thinking that the encoders themselves are 300 CPR encoders ?

And can 300 CPR ROTARY encoders be used with 300 LPI LINEAR strips ?

Thanks for any thoughts.

Alan






--

Alan Rothenbush | The Spartans do not ask the number of the
Academic Computing Services | enemy, only where they are.
Simon Fraser University |
Burnaby, B.C., Canada | Agix of Sparta