[FRC Blog] myRIO Expansion Port - What's the Deal?

[FrankJ]

Originally Posted by compwiztobe

FIRST probably won't allow any custom components in the power pathway. Only official KOP relays and speed controllers.

Rather, an active device is one that modifies the signal sent to the Talon or Spike (or Jag or Vic). If the connection to a speed controller is not directly from the roboRIO pins or MXP headers, through passive devices (PCBs, bumpers, etc.), to the speed controller signal port, then the intermediate device has to be approved in advance.

I have long since stop trying to predict what the GDC will do. But speed controllers & relays fit into the blogs definition of an active device. The proposed rule says one active device. NOT one active intermediate active device connected to a second active device. The blog has an approval process for active devices. Part of the approval process seems to be that you will need the resources to make the device commercially available to all the teams. So the approval bar starts off pretty high.

[Aren Siekmeier]

Originally Posted by FrankJ

I have long since stop trying to predict what the GDC will do. But speed controllers & relays fit into the blogs definition of an active device. The proposed rule says one active device. NOT one active intermediate active device connected to a second active device. The blog has an approval process for active devices. Part of the approval process seems to be that you will need the resources to make the device commercially available to all the teams. So the approval bar starts off pretty high.

I can see where you're getting this reading, but look at the other two options for controlling a motor or servo. It says directly connected to PWM pins or connected through passive devices, which obviously doesn't mean no speed controller/relay at all. The intent seems to be that all actuators are still controlled by the approved controllers (Talons, Vics, Jags, and Spikes), while the signals to these controllers can be supplied in the 3 ways described (direct connection, passive connection, or one approved active device).

But I agree both that the wording doesn't say this exactly and that we can't predict all of the GDC's intent or future actions.

[ice.berg]

Does anyone know what kind or type of connector is used? Its a 17x2 pin connector, but not sure on anything else of it. Trying to find a source for a female plug to adapt to it. Thanks

[Joe Ross]

Originally Posted by ice.berg

Does anyone know what kind or type of connector is used? Its a 17x2 pin connector, but not sure on anything else of it. Trying to find a source for a female plug to adapt to it. Thanks

The blog links to the NI MXP developers guide at https://decibel.ni.com/content/docs/DOC-39578 which gives several mating connectors.

[ice.berg]

Originally Posted by Joe Ross

The blog links to the NI MXP developers guide at https://decibel.ni.com/content/docs/DOC-39578 which gives several mating connectors.

Appreciate it, Thanks!

[FrankJ]

I think "passive" in First terms would include extension headers for the pins, wires, pcb traces, etc. Anything that does not modify the pathway. You make a daughter board that covers all the pins, but passively passes through the used pins. perhaps with a locking PWM connector that has the power & ground so you use a conventional PWM cable. Without allowing for the in the rules, an inspector somewhere would not let you do that.

The wording is the way it to allow for servos & VEX motors which take a direct PWM input well as conventional brushed motors & controllers.

[Alan Anderson]

Originally Posted by compwiztobe

I can see where you're getting this reading, but look at the other two options for controlling a motor or servo. It says directly connected to PWM pins or connected through passive devices, which obviously doesn't mean no speed controller/relay at all.

Servos do connect directly without an intermediate speed controller. So do some servo-like motors, though those might not be legal actuators.

[DonRotolo]

Originally Posted by FrankJ

So something like an Talon or an spike would be an active device. If you wanted to use a beefier relay than a spike, that would be an active device & would require submittable & approval.

Please bear in mind that "active device" and "ACTIVE DEVICE" are two different animals.

The former encompasses an awful lot of things
The latter is defined as something that fits onto the MXP and needs FIRST pre-approval.

Carry on...