Talon SRX Breakout Board

[DavidBlain]

Our team decided to try and create a breakout board for the new Talon since we are going to use the closed loop functionality of the device.

If you're interested in using the design, this page has the GERBER files (along with some warnings).

http://rosie.agawamrobotics.org/talo...reakout-board/

[ozrien]

Just in case you change your mind, or need something sooner, these will be available very soon at Vex and AndyMark.

http://www.vexrobotics.com/217-4398.html

[DavidBlain]

I saw those the other day. I was surprised that they didn't breakout the analog in or index pins.

[ozrien]

A 5V-Analog breakout is coming too that supports 5V analog sensors, and scales them to 3.3V so they are Talon SRX compliant.

The Index-pin use case isn't as prevalent as quadrature A/B, and we wanted the pads to be BIG while keeping the breakout SMALL. The goal is to be able to put the whole board inside heat shrink tubing.

[afiolmahon]

Hello Ozrien I had a quick question. Our team wanted to be able to use an indexed encoder with the SRX closed loop PID for absolute positioning. We were able to breakout the index pin from this board by soldering directly to the headers contact, but weren't able to find a way to set this up on the software end. Is this use case supported, or does the closed loop PID not handle an absolute position indexed encoder?

We are currently using this encoder in our configuration.

[ozrien]

The Talon SRX counts the rising edges on the index pin and sends it over CAN using the Quad Status Frame (See section 20.3. Quadrature Encoder Status in software ref manual).

So if you wanted to react to the index pin, you'll have to track it yourself. I figured when you see a change in the index rise count you could re-zero your quad position.

So how exactly did you want to use the index pin? Is quad A/B decoding not sufficient?

[wireties]

What kind of current can the Talon sink/source from the data port. I didn't see the spec in the manual. I'm thinking of hooking up an infrared emitter/detector.

TIA

[prifken]

Originally Posted by ozrien

A 5V-Analog breakout is coming too that supports 5V analog sensors, and scales them to 3.3V so they are Talon SRX compliant.

The Index-pin use case isn't as prevalent as quadrature A/B, and we wanted the pads to be BIG while keeping the breakout SMALL. The goal is to be able to put the whole board inside heat shrink tubing.

I'm glad you brought up the heat shrink; we weren't considering that. Breakouts should arrive tomorrow and we'll be able to test the SRX CAN fully this weekend.

[Hugh Meyer]

Omar,

The use case I would like is for the index pin to reset the quad counter. This would "rehome" the system each time around. Could you put that in please? The class would need a flag to pass if this feature should be activated or not since this would not always be the desired behavior.

We now are doing that in the main loop, but the response time creates hysteresis in the actual set point. If you do it in the controller it would be much tighter.

Please please please add this feature…you will be my hero!

Thanks.

Hugh Meyer

[Ether]

Originally Posted by Hugh Meyer

The use case I would like is for the index pin to reset the quad counter. This would "rehome" the system each time around.

Essentially turning it into an absolute encoder. Good for swerve steering angles etc.

[Jefferson]

Originally Posted by Hugh Meyer

Omar,

The use case I would like is for the index pin to reset the quad counter. This would "rehome" the system each time around. Could you put that in please? The class would need a flag to pass if this feature should be activated or not since this would not always be the desired behavior.

We now are doing that in the main loop, but the response time creates hysteresis in the actual set point. If you do it in the controller it would be much tighter.

Please please please add this feature…you will be my hero!

Thanks.

Hugh Meyer

Seconded.

[archer1223]

Team 1619 also did not like the breakout board avaliable. we felt it did not meet our needs. We designed and built our own Talon SRX Breakout board. We now have them install on our robot. They look and work fantastic.