encoders

[goofy173]

One of our programmers has heard that the standard encoders are not very accurate. We've never used them for any real reason. Do they work fine for normal use?

[Mark McLeod]

I'd suggest a link or make/model for what you think are standard encoders.

[Ether]

Originally Posted by Mark McLeod

I'd suggest a link or make/model for what you think are standard encoders.

...and also define what is meant by "normal" use.

[goofy173]

I found 3 of them in the electronics parts. I assume they came with the KOP in past years. That's why I call them standard.

Not sure the models because I'm not there at Robotics. I think they are all US Digital E4P-250-250-N-S-D-D-B encoder (am-0174). And also the one attached to the KOP item Gearmotor (PG71 gearbox + RS775 motor + encoder) which the encoder is a am-2816a Hall Effect Two Channel Encoder.

Not quite sure yet what speed the manipulator team is going to be running these at. Probably both less than 1000 RPM.

[FrankJ]

Properly done, they work well. Properly means the optic wheel is clean & undamaged. The shaft the optic wheel is on needs to be concentric & have very little end float. The optic wheel needs to be tight on the shaft & properly positioned. Other encoders that have their own shafts & bearings are easier to set up & use.

[Ether]

Originally Posted by FrankJ

Properly done, they work well. Properly means the optic wheel is clean & undamaged. The shaft the optic wheel is on needs to be concentric & have very little end float. The optic wheel needs to be tight on the shaft & properly positioned.

So very true. The above post is definitely a keeper.

[BitTwiddler]

I have a different question regarding encoders.

Has anyone used a Grayhill 61K128 encoder with the mini-toughbox?

That's what we're planning to use but I notice that it is a *very* tight fit with the body of the encoder right smack against the motor sides. We're using a 1/4" to 1/4" shaft coupling to connect the encoder to the output shaft. I'm tempted to take a file to the sides of the encoder body to see if we can open things up a bit. I'm worried about side-loading the encoder shaft.

[Jared]

Originally Posted by BitTwiddler

I have a different question regarding encoders.

Has anyone used a Grayhill 61K128 encoder with the mini-toughbox?

That's what we're planning to use but I notice that it is a *very* tight fit with the body of the encoder right smack against the motor sides. We're using a 1/4" to 1/4" shaft coupling to connect the encoder to the output shaft. I'm tempted to take a file to the sides of the encoder body to see if we can open things up a bit. I'm worried about side-loading the encoder shaft.

To avoid loading the encoder shaft, couple the two shafts with a piece of surgical tubing with the ends of the shafts inserted into the holes in the tubing and clamp it down with zipties. It works very nicely for misaligned encoders.

[CryptoStorm]

99% of the issue people have with encoders have more to do with the physical installation/positioning of the encoder than they do with the encoder themselves. junk data in, junk data out.