New Info on 2009 control system, maybe

[Kevin Sevcik]

Just got out a training seminar at NI HQ a little while ago, and I thought I'd note the interesting bits I saw. I don't think I've seen this in any of the online documentation, though much of it seems to be in the docs on the install DVDs. Much of the detailed info seems to be in the C/C++ programming guide, so this might be more benefit to those not getting an early kit. Also, keep in mind that all this is without considering the Rules. Just because it's possible doesn't make it legal. Also, just because the GDC declares something legal doesn't make it possible. Rambling commences:

Ribbon cables work well as the digital sidecar cables. It's possible to use ribbon cables to move the analog breakouts off the top of the cRIO, though they're obviously unshielded and more noise prone.

There are currently no provisions to power the Driver Station off the robot, though it's being investigated. I think it's pretty certain there won't be any power over the ethernet tether cable, so any power solution will be a separate cable.

Some joysticks Just Don't Work with the DS. Joysticks that actually need custom drivers (not configuration software) to work just in Windows are highly unlikely to work on the DS.

DS digital inputs require active termination. You can't simply close a switch to ground or 5V and assume the internals will pull it the other way when the switch is open. You need your own pull-up/down or need to connect it to 5V or ground.

We were warned not to try powering the Power Distribution board from a bench power supply (in lieu of a battery). Given the switching power supplies on the PD board, it could cause entrainment and subsequent power supplies meltdowns.

They're rapidly researching the effects of running the practice field wireless on the 2.4GHz band to make practicing safer. They need to determine the effects on any FTC competitions.

E-Stops now latch in the robot controller. This means after E-Stopping, you MUST reset your robot for it to function again. This would be to increase safety so an E-Stop robot can only be dangerous again after the robot was power cycled, not after the field is cycled.

Random: Jaguar powered CIMs are quiet. To my "mosquito" ringer deaf ears, anyways.

All the cRIO modules are technically optional. Removing unused ones won't affect the operation of others. We were told the analog module in slot 1 would be required by rule, as it will be used to monitor battery voltage for field troubleshooting.

There currently isn't any method for displaying custom text on the DS LCD. Chances are, you're going to want a dashboard PC. Also, in non-competition mode, the dashboard pc can receive camera images and communicate directly with the cRIO for debugging. Neither will be the case in competition mode. The former for bandwidth concerns, the latter for safety.

The image processing in Labview looks pretty powerful for machine-vision tasks. Also, there's a Labview Vision Wizard program to help you develop your image processing algorithms on a PC, so you can parallel vision development with control code development. Also, you can probe images on wires while the program is running. Let me repeat that. You can probe the results of your image filtering and processing algorithms at any point you choose in the process. With a simple right click of a mouse. In near real time.

Finally, a list of the FPGA/WPILib supported special peripherals, as best I can recall them. And all of this is without costing any processing power:
four, 4x quadrature encoders, with pulse width measuring
eight, 1x or 2x quadrature encoders or counters, with pulse width measuring
two, analog signal accumulators, which means two analog gyros
two, I2C buses (with two sidecars)
two, SPI buses (with two sidecars) plus chip selects (on Dig I/Os)
serial communications through the cRIO serial port

And that's all the rambling I think I can manage tonight...