Need help measuring RPM with the american Digital E4P-250 encoders

[SgtMartian]

My team is using Omni drive for the first time in years, and none of the current members have used it before. Our robot does not want to drive straight and we can't get all the wheels to spin at the same speed. We've done swerve drive in the past, so we've used encoders, but using them for RPM is confuzzling our programmer.

Whenever we give it a command for all the wheels to spin at the same speed in a strafing configuration, it slowly veers away, or simply goes nowhere near where we want it to. We managed to solve this problem when we just set the motor speeds to constants to move it in its different directions, however they were like .5,.6, and .8. They had to be very different. We don't even have rotational control set up yet. Everything else on the 'bot is good though.

We're trying to check the output shaft speeds to make sure that they are all the same using the boston Digital E4P-250.

We don't think the problem is mechanical, so can anyone enlighten me on how to fix the problem? I think it is a combo of just checking the motor speeds and weight distribution.

pls halp.