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Unread 29-06-2014, 11:25
Greg McKaskle Greg McKaskle is offline
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Re: Alpha Weekend #2, 2015 Control System

I'll add just a bit. Responses marked with ***s.

1. How are the times to deploy code, reimage, reboot, or connect?
*** Since the OS has protected processes, it is far less common to reboot, more common to restart. Reboot is similar to cRIO, but restart is about five or six seconds.

2. What is the overall quality of the board and its software?
*** One of the design goals/requirements was to be able to short any pin to any other on the board. Shorts and over voltage are indicated with LEDs and diagnostics. This is a new SW platform for NI, but several products have already released with it. I'm sure the beta will find some things, but it seems relatively robust entering beta.

3. Are there any tools to monitor the CPU/RAM usage of the system? If so, what is the typical usage?
*** The device hosts a Silverlight-based web page that is used for common configuration and monitoring. It shows CPU and resource on the page. You can also SSH and use top or other tools. Typical is too broad for me to give numbers for. But I'm happy with resource usage to this point.

4. Have you confirmed the brownout voltage, or seen any part of the system drop out?
*** This was a major focus of the alpha 2 weekend. Things are still being tweaked, but the robots were intentionally run with weak batteries to observe brownout behaviors of roboRIO, VRM, and PCM.

5. How well does CAN work? Are there still issues with floods of errors?
*** This is being entirely reworked to simplify device state management and error conditions.

6. I2C/SPI/Serial timing? Does it work?
*** I'm not sure what you are specifically asking about. These are included in the testing station with kit sensors.

7. Encoders-how fast with 4x sampling, can it still do averaging? Does it have issues with getRate?
*** Joe or Doug can answer this better than I. Ultimately, encoder rate will be significantly higher. I'm not sure what it is right now. Averaging is still present. getRate will still have noise issues near its limit.

8. How much of the linux operating system is exposed? Have you used any linux features yet?
*** 99.44%. I'm not sure I understand the question. We believe it is a good configuration out of the box, but you are the admin and it can be upgraded for other devices and libraries using standard mechanisms. I use the shell quite a bit.

9. We're one of those teams that just wants a single solenoid for shifting so we don't want the fancy pneumatics bumper, but we use more than 4 relays on most robots. How much current can the DIO source? Enough for a relay? Can the super expansion port do it?
*** Not sure I can do better than point you to the specs or ask for a more detailed question.

10. Most importantly, what are the plans for the cRIOs? Can we use them on a practice bot next year? When LV/windriver licenses run out, do we end up with really expensive paperweights? That would really suck. A lot.
*** Agreed. The goal is to allow them to be used for training, second robots, etc.

11. How robust is communication? How often is there an issue between any parts communicating with each other?
*** I'm not sure what devices in particular is being referred to. The USB connection vastly improves the imaging experience. The PC has a virtual NIC that bridges over USB. This auto assigns IP and doesn't go up and down during the imaging. Similarly, it comes up faster during reboots. CAN is being reworked to fail more gracefully when a cable or device fails. It also has full bandwidth since it isn't being bridged.

12. How easy is it to troubleshoot these issues?
*** Any in particular?


*** Another question was asked about the DLinks vs USB dongle. The plan was to develop and compare multiple options for robot communication. It was, unfortunately, not possible with the schedule and other constraints to make the roboRIO into a sufficiently good integrated wifi device. FRC demands are high, but volumes are low. The USB dongle was attractive, but bugs in linux drivers cause issues when used on an official field. This will be reevaluated when schedule permits. The DLink or a similar bridge solution was included as a known reference point. To this point it has been used in about one million official matches. Diagnostics and configuration improvements are underway. Additional communication options were investigated and some are still under evaluation.

Greg McKaskle
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