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No Data issue

 
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sevenracer



Joined: 25 Oct 2006
Posts: 7
Location: North Carolina

PostPosted: Tue May 15, 2007 9:51 am    Post subject: No Data issue Reply with quote

Hi,

I've been having a sporadic problem that I haven't been able to trace back to a hardware issue.

The system will come up and work normally, and then for some reason just stop working - displaying "No Data". This can happen after a few minutes, or a couple of hours - even in a stationary vehicle.

I have doublechecked all the connections, and I don't think they are an issue. I cannot induce the problem by moving the cables in any way.

If I exit flight and restart, or enter the flight config menu and click OK - the unit almost always starts working again.

My question is regarding how the SW behaves when it detects a "No Data" condition. Does the SW attempt to recover by closing and then reopening the Serial port? From my testing (unplugging then replugging the serial cable) it does not recover automatically.

I have a theory that the serial port driver is hanging for some reason, and needs to be restarted.

Any thoughts?

Thanks,
Neil
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Ed
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Joined: 27 May 2006
Posts: 280
Location: Seattle, WA

PostPosted: Tue May 15, 2007 5:03 pm    Post subject: Reply with quote

Hi Neil,

Yes, when the "No Data" condition is detected, the software closes and reopens the COM port. It will wait for a bit for new data, then close and reopen again if nothing comes in. It will keep doing this until data comes in or you exit Flight.

You should be able to randomly unplug the MQGPS and plug it back in and (after a delay) the data should come back online automatically. We have tested this extensively on the MQGPS-RS232 and the MQGPS-Bluetooth. Are you using the MQGPS-USB? The MQGPS-USB could be a different story. I would expect the COM port to disappear completely if the MQGPS-USB gets unplugged. If, as you suspect, the driver is hanging, then there's not much Flight can do.

Are you using a Pocket PC or a PC?

You might try checking "Is Bluetooth", with and without "Delay Bluetooth Init". The retry mechanism is somewhat different in that case, and it may give you a different result.

You may want to capture a debug log of the problem and email it to us. Check "Debug Mode" and "Log Serial" in MaxQData Setup > Settings > Advanced. You will find the debug files either in My Documents or on your storage card if you have one inserted in the Pocket PC.
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sevenracer



Joined: 25 Oct 2006
Posts: 7
Location: North Carolina

PostPosted: Wed May 16, 2007 7:58 am    Post subject: Reply with quote

Sorry for omitting info:

I'm using an industrially hardened PocketPC 2003 SE with a RS232 MQGPS.

I have tested disconnecting both the GPS receiver power and the serial connection, and the unit does not seem to recover when reconnected.

If I exit and restart Flight, or open the Sensor Config screen and click OK, it does start working again.

I will have to capture some debug logs for you to review.

Do you know the reason that I might be getting the no data condition? All my connections appear to be robust. Is it possible that the GPS receiver is getting hosed by noise on the 12V power from the car? I did notice that in the race car sometimes, when I reconnect, Flight shows the Satellite count at 20. That does not seem like it could be correct.

-Neil
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Ed
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Joined: 27 May 2006
Posts: 280
Location: Seattle, WA

PostPosted: Thu May 17, 2007 1:03 am    Post subject: Reply with quote

Hi Neil,

Hm, the RS-232 MQGPS historically has been a rock-solid solution and well-behaved when faced with an intermittent connection. But let me try to repro your problem. There could be something new. It will take a few days as I am out of the country right now.

Did this problem only start happening after a software upgrade? Which version are you using?

If the problem happens with the briefest of disconnections (e.g. less than one second), then I would think it is some sort of hardware problem. If a brief disconnection poses no problem but a long disconnection does, then I would think it's a software problem.

The fact that opening the Sensor Config screen and clicking OK clears it points to a possible software issue. A debug log would certainly help to nail it down.

It's theoretically possible that the unit is getting hosed by the 12V power, but it's unlikely. The most common cause of No Data we've seen with the RS-232 MQGPS is that the cigarette lighter adapter isn't held firmly in place and it backs out under vibration just enough to give an intermittent power connection. I would suspect this first, or other problems with the wiring.

The number 20 for Satellite Count is a special code used to indicate that you are receiving valid GPS position solutions even though the Satellite Count reported by the GPS module itself is 0. It's a workaround for a minor bug that causes the reported satellite count to drop to zero even though satellites are in view and the GPS calculations are working. It's unlikely it has anything to do with the No Data condition.
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targa86



Joined: 13 Aug 2008
Posts: 3

PostPosted: Wed Aug 13, 2008 6:33 pm    Post subject: Reply with quote

I had lots of Bluetooth disconnects also, turned out to be a loose battery. Shake your GPS unit to see if the battery is rattling around, mine was. If you connect to flight you can shake the GPS and check to see if this causes the "no Data" problem.

I fixed this by putting some electrical tape on the bottom and sides of the battery to make it fit tight. Now it stays connected no matter how hard I shake it.

Targa86
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