View Full Version : Talon sr, or SRX?
Mschmeh144
11-02-2015, 09:55
What type of talon are you using this season?
Personally, we are using at least six talon SRX controllers on our bot, I haven't counted them, but this may be a problem because we don't have enough spares. So, which talon would be more reliable to use, the SR or the SRX?
Also, is it possible to mix the two of them for use at the same time, not during competition, but on our test rig? Currently we have a testebed aptly named "ghettobot" which has four talon SR controllers but also has the option to use the two spare SRX controllers we have. Currently we just swap them using a few connectors when we need to work with the SRX, but would it be possible to avoid this and just leave them connected but disabled, as they are hidden under a platform attached to the robot and are hard to get to.
Thanks, any help would be appreciated
Alan Anderson
11-02-2015, 10:03
There's no problem in having a speed controller present and powered but with no motor connected.
Do not, under any circumstances, connect the outputs of two speed controllers together.
The SRs have proved to be very reliable so it is a tall bar for the SRXs to beat. The SRXs have more electronics in them, if you are not using canbus the Victor SPs might be a better choice. In either case neither have been out long enough to have fully established a reliability record comparable to the SRs.
While it is best not to mix controllers in a subsystem, I would hesitate to do it at a completion if that is was the only option.
MrForbes
11-02-2015, 10:12
We're late adopters. Six of the SR on our robot.
We're using five SRX's. The SR's were pretty good, but the SRX's blow them out of the water.
We're using five SRX's. The SR's were pretty good, but the SRX's blow them out of the water.
How so? Assume you are using PWM & no limit switches so you are comparing apples to apples.
Now if you are comparing Talon SRXs to Jag...
Mschmeh144
11-02-2015, 13:09
the talon srx has a closed casing, but so does the sr. the thing I don't like about the talon srx is the wires that come pre-attached. if you cut them or strip them you cannot make a mistake, or you've got yourself a useless talon. even the CAN wires come preattached, in the model that has them at least, im not sure if there is a PWM model.
also, its perfectly okay to have them plugged into the pdp and running on robot startup, but not connected to the motors?
We're late adopters. Six of the SR on our robot.
Same here.
There's no problem in having a speed controller present and powered but with no motor connected.
Good thing. We only have five motors (3 H-drive, 2 on lift). The sixth has leads with Anderson connectors on the end. We started laying out the board before we knew what we needed, and while we took the PCB off, we left the unused talons and spikes as spares. (We're using the spikes for lighting).
also, its perfectly okay to have them plugged into the pdp and running on robot startup, but not connected to the motors? Sure. It's a custom circuit consisting of a very high-value resistor.;)
We made a large investment in 24 Talon SRX's, as our design requires twelve and we're building a practice bot on top of the competition ones. So far, we've been VERY happy with them compared to the Jags we used previously.
Dunngeon
11-02-2015, 14:04
the talon srx has a closed casing, but so does the sr. the thing I don't like about the talon srx is the wires that come pre-attached. if you cut them or strip them you cannot make a mistake, or you've got yourself a useless talon. even the CAN wires come preattached, in the model that has them at least, im not sure if there is a PWM model.
also, its perfectly okay to have them plugged into the pdp and running on robot startup, but not connected to the motors?
There's quite a bit of wire on the SRX controller, it would take a large quantity of screw-ups to shorten the wire to the point where the SRX becomes unusable. If anything, the integrated wires are a plus because the electronics are physically isolated from the outside environment.
Mschmeh144
11-02-2015, 14:16
There's quite a bit of wire on the SRX controller, it would take a large quantity of screw-ups to shorten the wire to the point where the SRX becomes unusable. If anything, the integrated wires are a plus because the electronics are physically isolated from the outside environment.
This is true. But, accidents do happen. Especially with our testebed, which unexperienced members use like a toy.
For critical components, we're also late adopters. 8 SR's on our bot (1 spare).
Mschmeh144
11-02-2015, 14:25
We made a large investment in 24 Talon SRX's, as our design requires twelve and we're building a practice bot on top of the competition ones. So far, we've been VERY happy with them compared to the Jags we used previously.
We found it easy to just buy a ton of them too, but we didn't buy enough to have a spare for every one that we actually use. I am impressed with their closed casing, and the way they are generally built allows them to be packed tightly into small spaces. Otherwise, we would be using talon SR controllers instead. They are definitley a improvement over the Jags, but only time will tell how much of a improvement.
How so? Assume you are using PWM & no limit switches so you are comparing apples to apples.
Now if you are comparing Talon SRXs to Jag...
Talon SRX's use CAN, so we can get real-time data on the WebDashboard; they have passive heatsinking; they are microcontrollers, so the PID loop that controls them is offloaded; and it's almost impossible to get metal shavings in them.
Also CAN wiring is a lot better than PWM wiring.
jojoguy10
13-02-2015, 14:48
Late adopters here as well. 5 Sr's on ours.
some sr's and some VIC 888s and 884's
ILAMtitan
13-02-2015, 16:02
We have 9 SRXs on our bot this year. No complaints yet except our software team commented on some wonky embeded PID loop software, but they got it working.
All nine are on CAN. We crimped PWM cable headers to each end, one male and one female so that the chain has a single direction that can't be messed up. A small ziptie where the middle wire is missing keeps em together.
We also have sensor input directly into three of them (limits and an analog absolute encoder). Using a few free 10pin cables from Samtec we just made some custom adapters depending on what the sensor is. All in all, we're very happy.
No complaints yet except our software team commented on some wonky embeded PID loop software, but they got it working.
I don't think that's a fair characterization.
The PIDF in the SRX is meticulously documented in the SRX Software Reference Manual, and many teams have commented on how well it works. CTRE's chief software engineer Omar Zrien monitors these forums and stands ready to personally help any team having problems.
ILAMtitan
13-02-2015, 19:06
I don't think that's a fair characterization.
The PIDF in the SRX is meticulously documented in the SRX Software Reference Manual, and many teams have commented on how well it works. CTRE's chief software engineer Omar Zrien monitors these forums and stands ready to personally help any team having problems.
By wonky, I mean it didn't work the first time they tried it. 30 mins of actually reading the documentation fixed the problem. No complaints since it works well now.
page2067
13-02-2015, 23:29
We have 11 SR's on robot + 10 SR's + 1 Victor on practice.
We have obtained 5 SRX's but have not had time to explore them - and until then will stay with SR's. (yeah late adopters)
Intrigued by SRX's expanded functionality (CAN, local PID) - but not a priority at this point - Happy with SR's performance.
I suspect next year we will be using SRX's, maybe even later this year(?)
Optimism
16-02-2015, 13:23
We currently have 12 Talon Srx's on our robot, 8 of them for just swerve motors.
This year we are using six Talon SRX’s on our robot to have the ability to use CAN and to give our electronics a neater appearance.
jimbo493
21-02-2015, 23:01
We are using 7 SRXs and 2 New Victors, personally I love them in every way except the wire is permanently attached, I would love it it it they could be disconnected/replaced. I also love how much easier the CAN network is to use that the Jags.
Chadfrom308
21-02-2015, 23:07
How so? Assume you are using PWM & no limit switches so you are comparing apples to apples.
Now if you are comparing Talon SRXs to Jag...
They are not apples to apples, that's the point. This is our first year using CAN. I think the experience is going really well for us. The PIDs are great and the limit switch features are great too. The regular ones are just not as nice compared to the new ones.
With the new Talon SRXs, you can make a CNC machine with limit switches and servo control! It's great!
I do wish the pinout was bigger... anyways, I know our team had a great experience with them (so far, that is)
z_beeblebrox
21-02-2015, 23:15
6 SRX, all PID.
1 SR
MaGiC_PiKaChU
22-02-2015, 01:33
14 SRX, 12 of them in PID control :D
JDGallagher
22-02-2015, 02:00
14 of the SRX
6 SRX, all PID.
14 SRX, 12 of them in PID control
By these, do you mean CAN programming the set points, and on-talon PID controlling the actual output voltage?
If so (just curious) do you ever retrieve the position onto the 'RIO to make a true closed loop, or do you just use this as a "super-sized servo"?
evanperryg
22-02-2015, 11:55
8 SRX on our robot this year. They're awesome, particularly cause of their small size. My only complaint is the permanent wires. It basically forces you to place your motor controllers next to the PDP unless you want to add connectors, and if any of these wires gets damaged enough, it bricks the controller. CAN is really cool but I don't think it's significantly better than PWM. I feel that there is no "better" controller between the SR and the SRX, they both have their advantages and their disadvantages.
8 SRX on our robot this year. They're awesome, particularly cause of their small size. My only complaint is the permanent wires. It basically forces you to place your motor controllers next to the PDP unless you want to add connectors, and if any of these wires gets damaged enough, it bricks the controller. CAN is really cool but I don't think it's significantly better than PWM. I feel that there is no "better" controller between the SR and the SRX, they both have their advantages and their disadvantages.
Yeah, I'd agree, the SRX's size is great, but those permanent wires only allow you to do temporary connections on the other side, so you're kind of stuck with always using Anderson connectors. The SRs are great and reliable but take up more space. Also, make sure you wire them the right way, otherwise... You don't want to know, unfortunately our team does. ::ouch::
... My only complaint is the permanent wires. It basically forces you to place your motor controllers next to the PDP unless you want to add connectors, and if any of these wires gets damaged enough, it bricks the controller.
If you're using limit or PWM control within the SRX, wouldn't it make more sense to connect the controller directly (that is, connector-to-connector) to the motor, then use a long line from the PDP to the SRX so that the data runs are shorter? Only the power lines and CAN bus would need to come out from the control board, rather than all the sensor lines. (I'm presuming that the feedback sensors are located nearer to the motor than to the PDP.)
Alan Anderson
08-05-2015, 22:04
8 SRX on our robot this year. They're awesome, particularly cause of their small size. My only complaint is the permanent wires. It basically forces you to place your motor controllers next to the PDP unless you want to add connectors, and if any of these wires gets damaged enough, it bricks the controller.
I assume by "bricks" you mean something other than "makes it never work again"?
The wires are repairable/replaceable. We got a beta Victor SP that was non-functional out of the box. All we had to do was open it up and solder the green wire onto its pad.
The SRXs have far nicer wiring; even if you're using them in PWM mode, the ability to daisy-chain the built-in wires of multiple controllers that receive identical signals (e.g. in a drive setup) is extremely convenient.
They're also smaller.
10 SRXs on the robot, of which we used 8 (4 drive, 2 lift, 2 intake). We used a limit switch wired to a breakout board on the Talon. We also sell the breakouts if anybody needs them.
We wired some SRs on our 2012 bot today, and I was surprised at how much larger they are.
MaGiC_PiKaChU
10-05-2015, 00:40
SRX are awesome, because you can use their breakouts to connect encoders or limit switches. It makes your code lighter, and gives you more ports on the Rio. As an example, we'd use 8 PID subsystems with last year's talons. Now we have only one, because they are on closed loop.
TL:DR Talon SRX all the way
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