Chief Delphi - Reading Encoders?

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Questions4mQ202

21-01-2009 21:24

Reading Encoders?

There were many posts that were very useful regarding how to wire up the encoders (I believe, they were Andy Mark). But before we get into the fun stuff of splicing the wires, our adviser insists that we figure out how to read its output values, so Programming can do their job. Would anyone happen to know how we can test this?

Thanks much in advance!

elcron

21-01-2009 21:53

Re: Reading Encoders?

Are you using labview or C++?

If Your using C++ wpilib has an encoder class.

PHP Code:


		
			
Encoder *e = new Encoder(1, 2); //1 & 2 = your dig io pins for channel a & b

e->Start();

int distance = e->GetDistance();

// use distance for whatever you want

keehun

21-01-2009 23:03

Re: Reading Encoders?

The output values are easy to read. But they can be done only once you splice up the wires. I suggest you probe it on to a Oscilloscope and look at the quadrature signals. As you ramp up the motor, the signals should come closer to each other. If there's not a ton of noise, and if it looks "alright" then you should splice it. I wish they gave us two PWM outs instead of 1 4-lane cable.

Once you splice it and connect the correct A & B ports, then it's really simple, just go to WPI Libraries -> Sensors -> Encoders and do the usual thing with Open, Get, Close. Though, this time, you may want to fiddle around with the Configuring the Timers.

drkiraco

23-01-2009 19:19

Re: Reading Encoders?

It's pretty easy in labview. There's an encoder vi in the library. Just tell it what digital IO pins you've connected it to and that's all there is to it.

Quote:

Originally Posted by Questions4mQ202 (Post 805581)

dani190

23-01-2009 20:51

Re: Reading Encoders?

how accurate are your encoders? Our mentor says 1 of the values wasn't returning that well...

I think he said it know the distance but not the rotations or something...

Also do these break easy? im guessing we should have extras?

rwood359

23-01-2009 22:22

Re: Reading Encoders?

Quote:

Originally Posted by dani190 (Post 806841)

The encoders do not return the correct value for rate.
Here is the announcement of the bug:
http://forums.usfirst.org/showthread.php?t=11343

Here is the thread that isolated the bug:
http://forums.usfirst.org/showthread.php?t=11004

dani190

23-01-2009 22:27

Re: Reading Encoders?

ok so reading through the isolated thread, dont really see how to fix the issue...

sorry just clarify what you meant, isolate as in just push the problem aside? or isolate as in fix the rate problem?

Vikesrock

23-01-2009 22:40

Re: Reading Encoders?

Quote:

Originally Posted by dani190 (Post 806884)

By "isolated the bug" he means that it discovered the source. As indicated in the first thread that he linked to the bug is going to be addressed in the next software update.

dani190

23-01-2009 22:41

Re: Reading Encoders?

ok thanks a lot.

windell747

23-01-2009 23:51

Re: Reading Encoders?

does anyone know when the next update will be coming out?

Jared Russell

24-01-2009 22:23

Re: Reading Encoders?

I hope soon for our sake!

rwood359

25-01-2009 01:57

Re: Reading Encoders?

It went beta the first of last week - I thought it was going to be released by the end of the week.

Jared Russell

25-01-2009 20:28

Re: Reading Encoders?

The thread on the FIRST forums suggests a new update will be out tomorrow (Monday). The issue should now be resolved.

BradAMiller

25-01-2009 20:47

Re: Reading Encoders?

It's supposed to come out sometime tomorrow (Monday) and the encoder problem is fixed. If you were just reading distance or the count, that has always worked. The problem was just with reading the period or rate.

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