Re: 2015 Beta Testing - The Components are Here.
 

I've been looking for the weights of these components. Has anyone weight the beta components? I've looked in several places. The Fighting Pi weighed the alpha components without cases, but I haven't seen weights of the beta components with cases yet.

Re: 2015 Beta Testing - The Components are Here.
 

I should have posted that.

This is what Rosalie measured for the Beta components:

• roboRIO - 11.0 oz
• VRM - 1.8 oz
• PCM - 2.3 oz
• PDP - 1 lb 5.3 oz

Re: 2015 Beta Testing - The Components are Here.
 

Thanks Mark

Re: 2015 Beta Testing - The Components are Here.
 

We've had intermittent success with debugging with Java on the cRIO, more likely to work when tethered. With the roboRIO, they are asking each beta team to test debugging (for each language) so it should be solid.

Currently, there's been a few minor issues, which have been or are being worked on, however, we've had far more success debugging with the roboRIO then we ever had with the cRIO.

Re: 2015 Beta Testing - The Components are Here.
 

I have a few questions about the PCM and the 20A fuse. Others have expressed concern that the VRM and the PCM paired up on this fuse could approach 20A, and that this endangers the entire system since the radio will presumably be powered off of a 5V or 12V output. It sounds like Alpha teams did not have issues with this; we've yet to hear from Beta teams.

So while a single PCM and a single VRM may not be an issue, what about the possibility of more than one of either of these components. While needing 2 VRMs worth of voltage-regulated current is unlikely, it's totally reasonable to expect teams to want more than 8 solenoid channels for their pneumatic system. So here are the questions:

-Has there been any testing with multiple VRMs or PCMs on the designated, fused output? Does this present a significant risk of blowing the fuse and losing radio power?

-If this is the case, are there other options for powering additional VRMs/PCMs? Would a 20A breaker slot on the PDP be enough to protect their circuitry, and might this be included as an option in the 2015 rules? If someone has seen spec sheets for these components, please share them.

Re: 2015 Beta Testing - The Components are Here.
 

You should know better about asking for the rules before kickoff...
So multiples may or may not be allowed. Beta teams aren't on the GDC, :rolleyes: we're just trying to break things.

Personally, my team won't get additional PCM/VRM to test until December at the earliest, but we will test them when we are able.
We're doing our power extreme tests now, but haven't put max loads on the VRM/PCM yet.

No published power draw specs on the VRM/PCM components yet, but the math looks good and there doesn't appear to be any great risk of being constrained by the 20a PDP fuse, even if some strange game rule wiring scheme allows split wiring.

• 240w: a 20a PDP circuit at 12v will supply 240w.
• 45w: A VRM at max output will draw maybe 45w (12v*2a+12v*.5a+5v*2a+5v*.5a)
• 135w: A PCM at regular output will draw maybe 135w. Assumes an old Thomas compressor ~126w, plus (8) 1w per single solenoid coil or (4) 1w per double solenoid. Compressor startup draws up to 300w momentary, but handling that predictable one time surge is designed into the circuit. Longer compressor stalls are probably treated like short circuits and cut off - we'll test to see what happens in that case that later on.
• 5w to 9w: Additional PCMs will draw maybe 9w (single solenoids) or 5w (double solenoids) since multiple compressors aren't necessary.
• Both VRM/PCM have short circuit protection, so higher draws are prevented.

So,
240w = (45w+135w)baseline + a second VRM (45w) + a second PCM (9w) leaving breathing room.

I would recommend that 16 gauge wire be used if you start doubling up components for any non-FRC usage.

Re: 2015 Beta Testing - The Components are Here.
 

True, but a short on your compressor wiring, your PCM wiring, your VRM wiring, or your radio wiring will cause the radio to drop out for the entire match. Last year's radio supply powered the radio, and the radio only, and didn't have any non resetting fuses.

Re: 2015 Beta Testing - The Components are Here.
 

Actually, no a short will not cause this (except for radio short of course). That's part of the point.
We have already started shorting out the various outputs just to make sure.

Re: 2015 Beta Testing - The Components are Here.
 

That is good news that there is some protection in the individual modules, but that still won't protect that fuse from shorts at the PDB.

If there is a short between the wires that power the VRM or the PCM (not the loads connected to these modules), will the 20 amp fuse trip? This would be the same as just shorting the output of the 20 amp fused output on the PDB, so I'm assuming it would.

I have a fear of these hard to diagnose intermittents shorts after this season. We played with multiple teams (at least 4 that I saw) whose PWM outputs would drop out because of an intermittent connection between the DIO power pins, which caused the DSC's 5V supply to go out.

Re: 2015 Beta Testing - The Components are Here.
 

Any fault that cuts the power path to the radio, cuts the power to the radio. The fuse isn't going to matter, blown or un-blown it's already too late, the match is pretty much over.

Protection cannot do anything about a complete loss of power. It can only help prevent things that are bad from getting much, much worse.

Short protection has been greatly increased, so CTRE/NI have isolated faults to pretty much where they occur and not neighboring systems. roboRIO DIO shorts won't also take out the PWMs, but yea, if our wiring is bad, then there is no genie that will fix that other than our own electrical sub-team.

Beta teams will test the shorts that seem reasonable, so if you have ideas let all of us know. It might not be something we've thought of to test.

Re: 2015 Beta Testing - The Components are Here.
 

My biggest issue with the controls components we have been using is with the PWM cables and their lack of a locking device on the motor drives and Spike relays. With the amount of shock and vibration the robots get they will and do fall out unless something is done to lock them in place. The two most common methods I have found teams using are to either secure the cable near the connection meaning that the tiny wires are holding the connectors in place, or they use hot melt glue to glue them in place. Neither of these methods are acceptable on real automation equipment.

Hoe secure are the PWM connections on the new components?

Re: 2015 Beta Testing - The Components are Here.
 

But hopefully the rulemakers are reading these threads and listening to their beta testers. I was just asking if there's been any discussion of power alternatives for the radio/VRM/PCM.

Thanks for the numbers, that does make me more comfortable. It may be better to talk about current than power, since the power will depend on both current draw and Vbat (and power to start the compressor will depend on a lot of things including those, etc.). The fuse is sensitive to current only, and presumably the protection features in the PCM and the VRM are as well.

Not sure what stage you're at in the test right now, but I think many people would be interested in data regarding compressor current draw vs. time and pressure, if you can fit it in. EDIT: I should clarify: since this will depend a lot on the exact compressor model, maybe compare it to the current draw when running off a spike using pre-2015 control logic (hard starts), so we can see how the PCM manages the current draw.

Re: 2015 Beta Testing - The Components are Here.
 

In addition to say shorting the outputs of the VRM (ie does shorting a 12V take out the other 5V and 12V supplies and vica versa.

I'd be interested in any over-current on the VRM, ie what happens when something connected to the 12V 2A supply tries to pull 3A, and similar data for the other three outputs.

Re: 2015 Beta Testing - The Components are Here.
 

A couple of things we've learned - the PCM monitors the current draw to the compressor and protects against blowing the fuse. Beta testing will tell us just how smart it is, but so far I haven't heard about any of the fuses blowing.

We don't know that extra PCM and VRMs will be allowed under the rules, however the vendor suggested that additional ones could be powered from the 20/30 amp breakouts on the PDP.

In addition, (and this may have been just me), I had assumed that the VRM connections were individually rated at the amperages listed. However, the connections at each voltage / amperage rating share a rail. For instance, the 12V 2A connections are 12V, for a total of 2 amps. Not 12V 2A each.

Also, I strongly recommend visiting Mark's team webpage (358). The testing they've been doing is really above and beyond:

http://www.team358.org/files/program...stem2015-2019/

Re: 2015 Beta Testing - The Components are Here.
 

On the roboRIO, loose PWM's are our biggest complaint. We've already resorted to hot glue.