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#1
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Talon SRX Encoder Breakout
I had a question about the SRX breakout board for the new talon. Located here http://www.vexrobotics.com/217-4398.html
TChey way I understand it is you could add an encoder right to the tallon and it woudl process the signal on to the CAN bus. Correct me if I am wrong, the encoder would still be on the mechanical side to monitor the actual movement of the saft it will just feed data to directly the controller instead of directly to the myrio. |
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#2
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Re: Talon SRX Encoder Breakout
Yes i believe your right but I with this I believe you can also just have the PID control on the motor controller itself (eg keep a wheel spinning at 70 rpm)
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#3
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Re: Talon SRX Encoder Breakout
The reason to run the encoder to the talon is the same for the Jags. You would run the PID in the Talon. Otherwise you would run the encoder into the RoboRio.
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#4
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Re: Talon SRX Encoder Breakout
Also, because you can get the raw encoder values at any time, you can plug the encoder into the talon, then still do the PID calculation on the roboRIO. This has some interesting use cases, and could both simplify wiring, and require less IO's to be used for encoders.
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#5
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Re: Talon SRX Encoder Breakout
Wow, ok that makes sense. Its uses the encoder for the onboard PID. Nice. Originally I was thinking it would save an I/O and some wire but now I understand the PID can be offloaded from the myrio to the controller. I knew the new talon had PID but I never put the two together.
Thanks for the help all. Last edited by amesmich : 12-01-2015 at 08:53. |
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#6
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Re: Talon SRX Encoder Breakout
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#7
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Re: Talon SRX Encoder Breakout
The Talon SRX reports the sensor position and sensor velocity every 20ms. The control frame to the Talon is sent every 10ms.
If you are using C++/Java you can change these time periods. If you do this be sure to check the CAN metrics in the DS tab. See sections 20.5 and 20.7 in the Talon SRX Software Reference Manual for details. Also section 15 for measuring CAN performance. "Talon SRX Software Reference Manual 2014-12-26 (.pdf)" http://www.crosstheroadelectronics.c...ol_system.html |
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#8
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Re: Talon SRX Encoder Breakout
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#9
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Re: Talon SRX Encoder Breakout
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From what I read the values come back every 20ms. You get new values 50 times a second (20*50=1000ms=1 second) The update rate is at 10ms, so you can update it 100 times a second, You are using slightly stale data. At 10 fps (random robot speed that seemed reasonable) you will travel ~2.5 inches per 20ms period. But you are not going to stop on a dime ( or turn on one) since your 120lb robot moving 10 fps has a lot of momentum. Are the drive trains / actuators that sensitive to need higher update rates? Or is this just a case of faster is always better? |
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#10
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Re: Talon SRX Encoder Breakout
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In particular we are interested in how many pulses per second the Talon SRX is capable of reading from a quadrature encoder in CAN. |
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#11
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Re: Talon SRX Encoder Breakout
Just to be clear you went to ....
http://www.crosstheroadelectronics.c...ol_system.html ...and clicked on the "Talon SRX Software Reference Manual 2014-12-26 (.pdf)" hyperlink at the bottom and it redirected to Talon SR? Quote:
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#12
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Re: Talon SRX Encoder Breakout
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"www.crosstheroadelectronics.com/Talon SRX Software Reference Manual.pdf" in the lower left corner of my browser (Google Chrome) in a gray box. Then I click it and I end up here: http://www.crosstheroadelectronics.c...e%20Manual.pdf I'm no expert, but it might be helpful to change the " " (space) character in the file name and directory to an "_" (underscore). My browser seems to replace the space with a percent symbol and then direct me to the wrong page as a result. Last edited by KrazyCarl92 : 13-01-2015 at 13:19. Reason: added browser |
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#13
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Re: Talon SRX Encoder Breakout
Where does this take you?:
http://content.vexrobotics.com/vexpr...l-20141226.pdf It should take you to the software manual directly. Last edited by Bob Steele : 13-01-2015 at 15:02. |
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#14
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Re: Talon SRX Encoder Breakout
That's correct, space ' ' is encoded as %20.
Yeah I don't get it, both style paths seem to work for me, iexplorer and chrome. crosstheroadelectronics.com/Talon SRX Software Reference Manual.pdf crosstheroadelectronics.com/Talon%20SRX%20Software%20Reference%20Manual.pdf Anyone else having trouble? You can also just google Talon SRX Software Reference Manual. Also it's on vex's site http://www.vexrobotics.com/217-8080.html |
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#15
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Re: Talon SRX Encoder Breakout
I am able to access it from the vexpro site, thanks for pointing that out.
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