EMC problem ? RUT955 GPS recording stops & resumes sporadically

[Rakuda]

Hello out there,

I am using RUT955 in a RV-vehicle. On board cabin power is by 12V LiFePo4 battery system and RUT955 is permanently connected to cabin power. Cabin power and engine starter battery (12V lead acid) are linked by a Votronic vcc 1212-50 is a b2b charger without (!) galvanic isolation. The Votronic is a high end device: Votronic 3326 vcc 1212-50 12v to 12v 50a b2b charging converter

On some occasions, RUT does stop recording GPS data to the inserted memory card, but also sporadically resumes recording. Here is the relevant portion of recorded data. I am using the latest firmware, of course.

$GPRMC,150007.00,A,4759.283201,N,00747.925420,E,0.0,80.0,120124,0.5,W,A,V*6E
$GPGGA,150010.00,4759.283162,N,00747.925566,E,1,08,0.6,237.8,M,48.0,M,*69
$GPGGA,0,66
$GPRMC,V,N53
$GPGGA,0,66
$GPRMC,V,N53
$GPGGA,134838.00,4855.089867,N,00809.927714,E,1,08,0.6,111.4,M,48.0,M,65
$GPRMC,134838.00,A,4855.089867,N,00809.927714,E,0.0,0.0,130124,0.5,W,A,V53

I observe that RUT955 stopped recording after engine shutdown followed by an engine re-restart (diesel engine).
GPS recording eventually resumed after a further engine stop and restart the next day (no other system intervention during this time). There was another engine stop-start sequence during the GPS drop-out however, which did not trigger the GPS to resume recording.
Note that the RUT955 is permanently connected to cabin power and usually also records GPS data even while engine is not running. Most of the time GPS recording is not affected by engine stops and starts. The drop-out only occurs once in a while.

My suspicion is that some sort of Electromagnetic Compatibility issue with the power system may trigger GPS recording to fail but also to resume again.

Question 1: has anybody ever experienced the same problem on a vehicle mounted system ?
Question 2: could the problem be caused by some sort of Electromagnetic Compatibility issue (EMC) ?
Question 3: could some sort of noise filter in the power supply help ? which kind of filter could be used ?

Any suggestion welcome !

Regards, Mike.

[Daumantas]

Hello,

It’s hard to say what could be causing the issue here, as there are quite a few variables. You mentioned that there were issues after shutting down the engine, were there any other side effects like disconnected mobile connection or any other malfunction of the RUT955?
To prove or disprove the powering issue, if possible, I will ask you to test the RUT955 using the original PSU and 12VDC → 230VAC inverter. If the device remains stable, there may be another device in your camper connected to the 12V rail that is causing the interference, or perhaps there are some issues with the on-board charger.
Additionally, just in case this could be software-related, I will ask you to update to the latest firmware to rule out this possibility.

Thank you.

Best regards,

[Rakuda]

thank you so much for quick feedback.

The only other side effect may be manually executed a router reboot during the time of engine shutdown. I am not sure whether a re-boot was executed, I will check the log-file later today for that reason.

I will also check the firmware version and revert shortly. Telling out of memory, I had just recently updated to the latest version, just before the above event.

regards, Michael

[Rakuda]

Hello Daumantas,

the problem could be solved

after more in depth investigation, I found that the antennas AUX (LTE) and GPS/GNSS had been wrongly connected i.e. AUX antenna was connected to GPS socket and vice versa. Surprisingly the system worked quite well, but of course not in a reliable mode and maybe very susceptible for EMC interference. Now with the antennas correctly connected (GPS antenna in the GPS socket) the problem should be solved.

Nevertheless, thanks a lot for your quick attention to the issue, Teltonika’s good service it is very much appreciated.

Best regards, Michael

[Daumantas]

Glad to hear that the issue is solved!

Best regards,