Data Stream Won't Start (resolved) / RAILED

jdmjdm Columbia, MD
edited June 2019 in Cyton
This is embarrassing, but I can no longer get the data stream of my new Cyton to start.

I tried to follow the guide. I shut down things, put the dongle back into the computer first, start the Hub then OpenBCI GUI, turn on the board... (I also tried several slight variations on that)...

It looks like it finds the dongle fine, sees the channel, then tries to connect. I see the green and red lights on the dongle light up temporarily before it is just the blue light again.

When I start the data stream, nothing happens though. I am not getting any errors. It worked fine before...

Thanks!

UPDATE - it's working now (kind of? it worked for 1 second then it just said RAILED for all channels). Vert Scale Auto. I tried toggling the Window and other settings. Accelerometer looks OK.

I don't know what changed to make it start working at all. Also, I'm not sure what RAILED means... no signal? Too much signal?

Comments

  • jdmjdm Columbia, MD
    edited June 2019
    I found a post about changing the pins to the lower set instead of the upper ones. http://openbci.com/forum/index.php?p=/discussion/220/channels-stuck-at-railed

    That seemed to help. 1 channel shows a data stream. 1-2 others show up randomly for 1 second at a time. The rest of the time it says RAILED.

    What does that mean? What can you change to avoid RAILED?

    I notice on the left they all have the same greek letter (omega). Does that imply some sort of filtering going on that may be causing this? i see the 15 - 50 Hz BP filter that can be toggled. That's a different filter? Or I guess that's the only filter and the Omega means something different?

    UPDATE: This post http://openbci.com/forum/index.php?p=/discussion/1496/all-channels-railed   helped a lot. I just put more pressure on the headband and it helped the data show up. Still.... understanding the definition of RAILED would help a lot, as well as the Omega, etc. Thanks! William and PushtheWorld's old posts helped a ton.

    UPDATE: Just when I thought it was working... channel 2 never showed data no matter what I did. Then I tried swapping channels 1 and 2 to see what happened. No only did it not work, it looked like the wave data didn't change much when you completely unplug the leads from the pins....
  • wjcroftwjcroft Mount Shasta, CA
    edited June 2019
    JDM, hi.

    As you've seen from the other 'RAILED' threads, RAILED just means that the current channel values exceed what can be shown at the current Time Series scale factor. Or if 'Auto' is selected, the channel values exceed the maximum allowed by the ADS1299 A/D converter. Generally this means you just have a bad scalp connection.

    In rare cases, for say millivolt level signals (EMG, ECG), changing the GUI 'SETTINGS' (not just Time Series) channel Scale Factor from the default (x24), to a lower value may result in the RAILED going away. But if you are using EEG with a headband, the solution is better scalp contact.

    Regards,

    William

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