Encoders getting different rates

[jhellr13]

Originally Posted by tilky

ok so since they both work, but at different rates, the method i gave above will work.

Exactly. In my code right now I just have the distance per count set at 1 for both and they are both at 1X. I'm just going to lay out 10ft, push the robot, get the readouts for both, divide 10ft * 12 inches by the count for each side. Then I will have the distance per count for both. If that goes the way I think, both encoders will be in sync with each other afterwards. What do you think?

[tilky]

it sounds perfect. and this test will kill 2 birds with one stone; you will be able to find the counts per foot at the same time

[jhellr13]

Originally Posted by tilky

it sounds perfect. and this test will kill 2 birds with one stone; you will be able to find the counts per foot at the same time

Great! Thanks for the help. See you guys next month at Hofstra

[tilky]

what school are you from?

[Alan Anderson]

Originally Posted by jhellr13

I'm not exactly sure of the entire model number as I don't have them in front of me, but I definitely know one is all Ds and the other has Ds and a H.

The letters don't tell you how many counts per revolution the encoder provides. That's in the numbers. The E4P encoders used on AndyMark gearboxes have a "250" in the part number that refers to the 1/4" shaft they go on, but they have another three-digit number that's the important one here. The KOP encoders have been 250 or 360 counts per revolution.

Find out what the full part numbers are and you'll probably see why one of them is reporting much smaller values.

[jhellr13]

Originally Posted by tilky

what school are you from?

Comsewogue

[tilky]

ummm....where is that?

[jhellr13]

Originally Posted by Alan Anderson

The letters don't tell you how many counts per revolution the encoder provides. That's in the numbers. The E4P encoders used on AndyMark gearboxes have a "250" in the part number that refers to the 1/4" shaft they go on, but they have another three-digit number that's the important one here. The KOP encoders have been 250 or 360 counts per revolution.

Find out what the full part numbers are and you'll probably see why one of them is reporting much smaller values.

That could be it. I'll look into it

[jhellr13]

Originally Posted by tilky

ummm....where is that?

Suffolk county...

[tilky]

ok. i'm guessing you know where connetquot is, so see you there

[Brandon_L]

We had the same problem with ours. One side was giving reliable readings everytime, the other would give us some random garbage. We figured it out by manually rotating the axis the encoder was on by 1 revolution, and looking at the output, several times. They were very consistent, compared to the other side that would give us garbage. We looked at our wiring and found that the plastic clip the wires plug into was cracked and one of the signal wires was pretty much not connected. Pull it out and just check on it. After we replaced it, its been working fine.

If you rotate them one revolution and both sides are giving similar readings every time, then you can go ahead and scale them. For example if side A was giving you 140 and B was 360, you know that 140X=360. 360/140=~2.6. So you multiply the one side by ~2.6 to get them equal.