Re: Encoder Wiring Help Needed
 

I dont recall doing that, but no it wasn't to your two part question.

Re: Encoder Wiring Help Needed
 

Wait...
I just found a different class module (GearTooth class). This one accepts one channel. So it does support counting one channel. I suppose you can connect the A channel to one digital input and use the GearTooth class to access the count.

Re: Encoder Wiring Help Needed
 

To honest with you I know nothing about code. The most i know is that we use Java lol. I'm more of a mechanical/ electrical guy.:rolleyes:

Re: Encoder Wiring Help Needed
 

Interesting...
From reading the source code of the GearTooth class, it seems the GearTooth sensor can even tell the direction. It supports different pulse widths on different directions. I wonder how does that work? But I am sure it is only specific to the GearTooth sensor. If you use one channel of the optical encoder, since the pulse width doesn't change in both direction (except for changing speed), it cannot decode the direction from the pulse width.

Re: Encoder Wiring Help Needed
 

Just found this thread:

http://www.chiefdelphi.com/forums/sh...d.php?t=101587

Re: Encoder Wiring Help Needed
 

Yep, there is also a counter class that can be used for this purpose.

Re: Encoder Wiring Help Needed
 

I am assuming that the counting is being done by the FPGA hardware. Otherwise you'd swamp the cRIO with interrupts.

Re: Encoder Wiring Help Needed
 

Yep, the counting is done by the FPGA.

Re: Encoder Wiring Help Needed
 

Does it say that explicitly in one of the documents you've just been reading?

Re: Encoder Wiring Help Needed
 

It's in the source code of counter.cpp. It's accessing the FPGA all over.

Another issue with encoders to keep in mind is the "sense" of forward and backwards. Especially if using the encoders with jaguar PID loops, but even with cRIO PID loops, the encoders need to be increasing when the motor is going forward, and the control input sense of forward needs to match the encoder. And the jaguar's sense of positive voltage needs to match also. You may need to reverse the A and B lines of the encoder, or the polarity of the motor, to get these things all having the same definition of "forward". If you add limit switches to the mix, the forward and reverse limit switches must also correspond.

Re: Encoder Wiring Help Needed
 

Very timely discussion. I am going to make the assumption the LabView VIs associated with the counter implement this class for us to use to count shooter revolutions.
Thanks guys.:D

Re: Encoder Wiring Help Needed
 

Not sure where to go. I have wired these encoders using the 2 channels on the sidecar. When I do, the robot goes nuts. It spins one side drive backwards and the second side does nothing and never works. Have wired +5, gnd, signal A to first channel and signal b to second channel on both sides. Anyone have an explanation as to what is going on.

Re: Encoder Wiring Help Needed
 

An Update:

For you Labview programmers only interested in looking at one input to count pulses to determine the rate of rotation, the WPI counter library works great. Just make sure you take the time to read the help file on the counter VIs thoroughly.

When I got to the shop earlier today the team programmer complained that the software based counter he had built couldn't keep up at high motor speeds. I explained how the FPGA offloaded this work to the hardware and the counter VIs in the WPI library took advantage of this capability. We tried them and they worked all the way up to the 4000 RPM speed with no problem. We found it helpful to use one of the low-pass filters from the PID library.

Re: Encoder Wiring Help Needed
 

What is your program doing to control the drive motors? Are the encoder readings used to compute the commanded motor power?