Problems with Victor 884

[Alex Dinsmoor]

The electrical team (and me) met today to finish installing the new control system and we ran into a problem. Our Victor 884 PWM's do not work with the on board code provided by FIRST. We were wondering if
1) Any other teams are having this problem
2) We are required to use the Jaguars this year
3) We could program the DS to use the Victors

We know that everything works, because we tested a Jaguar also and it worked fine.

Any information would be extremely helpful to the FEDS.

Thank you,
Alex Dinsmoor
Team 201
Programmer/Electrical

[ATannahill]

Jaguars are not mandatory, victors will still be available. Did you check the programing to see if it is set for jags or 884s? Also what do you mean by

3) We could program the DS to use the Victors

The DS has no programing except firmware and team number, possible you were talking about the cRio.

[AdamHeard]

Victors are legal, but I believe you must change the code to the specific speed controller (and it's set to jaguars by default) as it generates a different PWM for each type.

[Alex Dinsmoor]

Originally Posted by rtfgnow

Also what do you mean by The DS has no programing except firmware and team number, possible you were talking about the cRio.

Yeah I meant the cRio, it's been a long day of working/school

Originally Posted by AdamHeard

Victors are legal, but I believe you must change the code to the specific speed controller (and it's set to jaguars by default) as it generates a different PWM for each type.

That's good to hear. We were going to reuse our old electronics board, and didn't want to use the jags because of their size. Once we begin to program we will be sure to take note of that

[trilogy2826]

I know the large size is an immediate turn off, but please keep an open mind about using the Jags. The linearity and slow speed control compared to the Victors is night and day. See www.chiefdelphi.com/forums/showthread.php?t=68714 for more info on this. If you are serious about accurate controls this year make sure you make an effort to test them out.

[Joe Ross]

Originally Posted by AdamHeard

Victors are legal, but I believe you must change the code to the specific speed controller (and it's set to jaguars by default) as it generates a different PWM for each type.

The difference between the victor, jaguar, and servo code will not keep any of them from receiving a signal if programmed for another type. If a Victor is programmed with the Jaguar class, the victor's output will saturate very early. If a Jaguar is programmed with the victor class, the Jaguar's output will never saturate. The deadbands and neutral points will also be a little off.

I'd guess that the problem is that the PWM cables aren't plugged in fully on the Victor. It can be quite difficult to get it in, because of the retaining features.

[Alex Dinsmoor]

Originally Posted by Joe Ross

I'd guess that the problem is that the PWM cables aren't plugged in fully on the Victor. It can be quite difficult to get it in, because of the retaining features.

Hmm, that could be it. I will be sure to check those the next time we meet.

@trilogy2826 I will need to investigate into the jags further. Is it possible to make a tower of sorts out of two of them? I know you need a half inch clearance between them, but in order to fit them on we would need to do something along the lines of stacking to be able to have enough space.

[Al Skierkiewicz]

I would not stack either type of speed control. The top of the fans on both types need to be free to move the cooling air over the power devices. The size of the Jaguar is a distinct downside to using these devices in comparison. Remember that in all electronics there is a point on the temperature curve where the device just starts to do what it wants. Sometimes to the point of self destruction.

[Sam2197]

do the jags have a feedback for speed so that you can sync all the motors to the same speed to make sure you go straight in auto.

[Kingofl337]

Not till CANBUS next year.

[Alex Dinsmoor]

Originally Posted by Al Skierkiewicz

I would not stack either type of speed control. The top of the fans on both types need to be free to move the cooling air over the power devices. The size of the Jaguar is a distinct downside to using these devices in comparison. Remember that in all electronics there is a point on the temperature curve where the device just starts to do what it wants. Sometimes to the point of self destruction.

That's a good point. I don't want our robot to just go out of control!

Is there anything we can possibly put the jags over on a raised platform?
Here is our electronics board (sorry for so so detail): http://www.chiefdelphi.com/media/photos/32126

[Al Skierkiewicz]

Alex,
Normally I suggest that speed controllers be mounted near the motors they are controlling to minimize the wire runs. There is nothing in the picture to prevent you from using perf stock or a piece of lexan on the uprights across the back of the robot. Then you can mount the controllers vertically on that. Since the Jaguars have mounting holes in the sides, you can use threaded standoffs to elevate every other one and using the standoffs, rotate the elevated controllers 90 degrees to allow you to stagger them and fit more in the space. That way, no fans are occluded and the wiring is spaced out. Also, mounting the controllers so that they are front to back rather than side to side, works well too. This allows them to be mounted next to each other and touching. The wiring works better that way as well and the only drawback is getting the PWM cables attached. In your actual robot, don't forget to mark your wires and controllers. You can get 3M wire marking tape from Digikey. It is expensive (about $30 for a dispenser with all 10 EIA colors) but is well worth it when you are trouble shooting.

[DonRotolo]

Originally Posted by Joe Ross

The difference between the victor, jaguar, and servo code will not keep any of them from receiving a signal if programmed for another type.

We completed out Out of The Box test last night, with one Jaguar and one Victor connected - both worked fine (with the effects Joe noted) with no changes to the OTB code.

Stacking anything that tends to generate a lot of heat isn't always a good idea, but in some cases if you manage the heat other ways, it's not always fatal. One example is if it controls a small load, just a few Amps (and thus doesn't get that warm), another example is if there is natural or forced airflow that ensures good cooling.

[Alex Dinsmoor]

Originally Posted by Don Rotolo

We completed out Out of The Box test last night, with one Jaguar and one Victor connected - both worked fine (with the effects Joe noted) with no changes to the OTB code.

Did you use the new Victor that came with the kit, or an older one from a previous year?

Originally Posted by Al Skierkiewicz

Alex,
Normally I suggest that speed controllers be mounted near the motors they are controlling to minimize the wire runs. There is nothing in the picture to prevent you from using perf stock or a piece of lexan on the uprights across the back of the robot. Then you can mount the controllers vertically on that. Since the Jaguars have mounting holes in the sides, you can use threaded standoffs to elevate every other one and using the standoffs, rotate the elevated controllers 90 degrees to allow you to stagger them and fit more in the space. That way, no fans are occluded and the wiring is spaced out. Also, mounting the controllers so that they are front to back rather than side to side, works well too. This allows them to be mounted next to each other and touching. The wiring works better that way as well and the only drawback is getting the PWM cables attached. In your actual robot, don't forget to mark your wires and controllers. You can get 3M wirk marking tape from Digikey. It is expensive (about $30 for a dispenser with all 10 EIA colors) but is well worth it when you are trouble shooting.

All of these are really good ideas, I will be sure to pass these along to my mentor! I'm glad we used zip ties to attach all of the components of our electrical board, now no one can make to big of a fuss if we decide to rearrange the board.

[DonRotolo]

Originally Posted by Alex Dinsmoor

Did you use the new Victor that came with the kit, or an older one from a previous year?

It was an older one from a previous year.