Optical encoders and LabView

[autox_vette]

Our controls team has been experimenting with adding encoders (standard US Digital E4P-250 series) onto the toughboxes on our robot from last year to get more experience with integrating them. We have been having problems with getting accurate readings from them (one side or the other reading as much as 50% more than the other).

We found that the encoder wheesl on all of our encoders (we've tried several) are very "gunked up" (technical term), so we have new ones on order, but as we swap the encoder wheels from side to side, the erroneous readings don't always follow the wheel, I'm wondering if we also have some kind of programming error (I'm relatively new to labView and still trying to figure out all of the interactions) which is adding to our confusion.

We opened the standard encoder example and copied the entire VI to create a second loop so we could read the values on both sides of the robot as we roll it across the room. Sometimes one reads 50% more than the other, sometimes 25%, etc.

Can someone with experience with encoders in labView comment on whether what we did is correct or not.

Thanks,
Kenton