No Connection on Power Up

If a device is not connecting, it is usually power or SIM related.

Check that the device is powered:

  • If using an internal battery, it should be above 3.5V for a reliable connection.
  • If using external power, the device should receive 7 – 35V on the red wire on the harness, and ground on the black wire. If using a different harness, ensure the polarity is correct. It should draw 20 – 100 mA on power up.

The LED on the PCB should illuminate. If it switches on briefly and goes off, it may indicate that the power is not sufficient for the device to boot. It will wait until either external power is above 7V or the internal battery is above 3.5V. If either condition is true, the LED will start to flash slowly.

Check that the SIM is in order:

  • The SIM is installed with the correct orientation, and the holder is properly latched.
  • The SIM PIN is either not set, or is set to the Dart’s PIN. The PIN can be retrieved from the OEM Server web interface.
  • The SIM has credit / airtime.
  • The APN is set correctly: a new Dart will be set to Auto-APN unless your distributor has made special arrangements. An in-service Dart may have been configured with a specific APN in the past. To be certain, you can SMS the APN settings (see section 8.3).
  • The LED will flash slowly until it connects to the server. Once connected it will flash fast. If data is sent, it will got solid briefly and revert to flashing fast.

Forcing a Connection

There is no way to initiate a connection remotely because when the device sleeps, it switches off its modem. You will need to wait for the next scheduled connection – either a heartbeat, trip start or input change.

If you have the unit in your hands, you can force a connection by toggling external power. An external power change triggers an upload. Ensure the change is long enough to trigger the external power debounce period – 2 seconds by default.

You can also change any of the inputs set to trigger an upload. Usually ignition will trigger an upload. This depends on the system parameter configuration.

Debugging with OEM

The OEM Admin Interface is a powerful tool for understanding what your device is doing. See the OEM guide for detailed instructions. The following notes may help:

  • Check when it last connected and if it committed records successfully.
  • Check external power and internal battery level.
  • Enable the log capture. Normally the OEM server forwards logs to the 3rd party software platform. Enable the capture of logs by selecting the device; going to Device Operations->Set Data Capture Expiry; select a date in the future when the server should stop the capture; click OK. View the logs in the Device Details->Logs tab.
  • Enable debugging for a module. Do this by selecting the device; going to Device Operations -> Set Device Debug Flags; set the module of interest to the required logging level; select an expiry date when the debugging should end; click OK. View the logs in the Device Details->Logs tab

GPS troubleshooting

For detailed GPS troubleshooting, GPS debug message can be enabled on OEM Server. When the debug level is set to Info, GPS debug messages will appear in the log. In addition to individual fix times, signal level diagnostics whenever a fix takes longer than 36 seconds, or the GPS decides to stay awake after a fix to collect more satellite information. Please note that while debug messages are enabled, uploads will use extra data.

The GPS debugging can be enabled on the OEM Admin Interface by selecting the device; going to Device Operations->Set Device Debug Flags; set GPS to Info; select an expiry date when the debugging should end; click OK.

The diagnostics will be available on the OEM Admin interface. Click device details and go to the logs tab. 

Uploaded debug messages will look like this:



Debug[GPS][Info]: TTFT=0s

Time taken for GPS to determine the time. Usually 0 or 1 seconds.

Debug[GPS][Info]: TTFF=3s PDOP(x10)=23 3Dfix=1

Time taken for a basic GPS fix. Usually between 1 and 36 seconds.

Debug[GPS][Info]: Valid=3s PDOP(x10)=23 3Dfix=1

Time taken before a GPS fix passes additional validity filters. Usually TTFF + 0 to 3 seconds.

Debug[GPS][Info]: ORB 54,4,10

Known orbitals. In this example, of 54 possible orbitals, 4 are known in detail, and the knowledge is useable for the next 10 x 15 minutes. Detailed orbital knowledge is not required for a fix, but can speed up the process.

Debug[GPS][Info]: SAT22 43402,43723,40663 …

Tracked satellites. In this example, 22 simultaneous channels are active (locked or searching). The best ten satellites are listed, with the first two digits of each number being the signal to noise ratio – 43, 43, and 40 dB Strengths above 25 are useable, above 35 are good, and above 45 are excellent.

Poor Movement Trip Start Performance

If movement trip (emulated ignition) starts are poorer than expected, check the following:

What is the movement threshold? The default is 150m. Reducing this may result in false trip starts.

The GPS may have taken a long time to lock, due to poor signal or a fault. See GPS Troubleshooting above. Check the quality of the fix and the time to first fix.