Talon SRX and Analog Encoders

[TBots]

Ether, what did you mean when you said this?

Originally Posted by Ether

use the appropriate CAN commands to set the gains in the Talon's PID controller.

Do you mean the difference in the current position of the encoder and the set point?

[MaGiC_PiKaChU]

Originally Posted by TBots

Ether, what did you mean when you said this?

Do you mean the difference in the current position of the encoder and the set point?

You have a command probably called "SetPID"... It allows you to place your parameters for the PID control, when you control with the position. You call this once before your control loop. if you never worked with PIDs before, I'm pretty sure Ether could help you

[Ether]

Originally Posted by TBots

Do you mean the difference in the current position of the encoder and the set point?

No. Watch this video. It explains what PID gains are.

[TBots]

Ah I see, you just mean the constants associated with PID. I understand now.

How frequent is the tele-op code executed on the roboRIO?

I need to know so I can choose the sensitivity of the joystick. Ill then use the values of the joystick in the math for the set point.

[Ether]

Originally Posted by TBots

I need to know [TeleOp frequency] so I can choose the sensitivity of the joystick.

Please explain in a bit more detail what you mean.

[MaGiC_PiKaChU]

Originally Posted by Ether

Please explain in a bit more detail what you mean.

pretty sure he means how many times the roboRio runs the teleoperated loop very second...

I guess it depends how much code you run... you can find the number of iteration by printing the time each time you enter the loop... I don't know how that is useful for your PID control tough

[Ether]

Let me try again:

Originally Posted by TBots

I need to know [TeleOP frequency] so I can choose the sensitivity of the joystick

@Tbots: ..Please explain in a bit more detail the relationship between the TeleOp frequency and the bolded portion above.

[TBots]

In order to scale -1 to 1, the normal scale of the joystick, to 0 to 1024, we would have to add one and multiply by 512 the original value of the joystick. The problem is, since we would be using a joystick, whoever was driving would have to hold that position on the joystick else the wheel would return back to the the 512th position.

The only way I can think to avoid this, is if a button would increase the value of the angle while another one lowered it. The only problem is I'd have to know how often the tele-op vi was executed. Otherwise I wouldn't know by how much to increase the value. In other words, I wouldn't know how sensitive to make the joystick.

In the case that the button was held down, the wheel may have too large of an increase in angle and mess up the wires of the wheel. This is why I'd need to know how long it takes tele-op to execute, in order to determine what magnitude the decrease/increase would need to be.

[TBots]

MaGiC_PiKaChU, when connecting the encoders with the data cable and using a breadboard and resistors, how did you connect the data cable? It has two rows of holes in it, each with 5 holes. 2x5. How did you connect these to the breadboard?

Also, do you have to have a d-link connected to the robot in order to enter web-based configuration? We've never used web-based configuration, but we need to use it to configure the SRX.

[randantor]

In LabVIEW, the Teleop VI runs every time the robot receives a packet from the driver station, so the delay could be pretty irregular.

A way to achieve what I think you're looking for would be to measure the time delta between each run of Teleop, and multiply that by the joystick value before applying the scaling factor and integrating, to ensure that the joystick power is being applied "evenly" with respect to time.

For example:

[MaGiC_PiKaChU]

Originally Posted by TBots

MaGiC_PiKaChU, when connecting the encoders with the data cable and using a breadboard and resistors, how did you connect the data cable? It has two rows of holes in it, each with 5 holes. 2x5. How did you connect these to the breadboard?

Also, do you have to have a d-link connected to the robot in order to enter web-based configuration? We've never used web-based configuration, but we need to use it to configure the SRX.

1- we had tons of data cables, so we cut one side to connect each wire individually... you could also plug a small wire into each hole, but that would be harder

2- No, your RoboRio has its own IP address, it changes if you connect via USB or ethernet. I don't remember the defaults, because we changed it to 10.33.60.2 as soon as we got it. You can find this address somewhere in the user's manual

[TBots]

Originally Posted by MaGiC_PiKaChU

1- we had tons of data cables, so we cut one side to connect each wire individually... you could also plug a small wire into each hole, but that would be harder

Cutting them would make it hard to plug them into the breakout board later. Just the same, we have had a lot of difficulty trying to find wires small enough to fit into the data cable's slots. Do you know what each hole does on the data cable?

Originally Posted by MaGiC_PiKaChU

2- No, your RoboRio has its own IP address, it changes if you connect via USB or ethernet. I don't remember the defaults, because we changed it to 10.33.60.2 as soon as we got it. You can find this address somewhere in the user's manual

The IP changes?? you mean it's not “roborio-XXXX.local”
where XXXX is the team number? It has an extension such as .2 or .6?

[TBots]

Originally Posted by randantor

A way to achieve what I think you're looking for would be to measure the time delta between each run of Teleop, and multiply that by the joystick value before applying the scaling factor and integrating, to ensure that the joystick power is being applied "evenly" with respect to time.

I've never heard of measuring time, but it sounds like a great idea! Ill see if I can find it.

Thank you for the help!

[MaGiC_PiKaChU]

Originally Posted by TBots

Cutting them would make it hard to plug them into the breakout board later. Just the same, we have had a lot of difficulty trying to find wires small enough to fit into the data cable's slots. Do you know what each hole does on the data cable?

see my thumbnail

Originally Posted by TBots

The IP changes?? you mean it's not “roborio-XXXX.local”
where XXXX is the team number? It has an extension such as .2 or .6?

I don't remember... as long as you find the right IP you'll be able to configure your SRX... I always connected using 10.33.60.2, in my case