Determining the cause of red or yellow flashing LED

This document applies to both the Opal and access point.

A red flashing LED indicates an error has been encountered, while a yellow flashing LED indicates that a warning has been encountered. If the LED is flashing red but very fast, it indicates a critical error. Note: The green LED seen in the Opal's normal operating mode will change to yellow when the battery is getting low. This is different than the faster (1/s) flashing that is displayed when a warning is encountered.

When an error is encountered, there will be a line of text displayed at the bottom of the main screen on the Opal indicating the issue. Often, this is sufficient to pass on to support if it cannot be resolved, but more specific information about the error can be retrieved and provided to customer support. To determine the more precise cause of the issue, press button #2 (the one near the lower right of the display) three times will get you to the device status screen.

There are two sections to the device status screen. The top one has the header "Device Status States", and indicates the currently asserted states. Below that is a header titled "Status State Counts". This lists the total number of times different states have been encountered.

When the LED is flashing red or yellow, it means that there is a currently asserted state that will be listed in the "Device Status States" section. Sometimes, these errors are descriptive enough to make sense of, but often they are not. If it is not clear what the issue is, contact APDM customer support at and write down the currently asserted states. Don't bother writing down the states indicated in the "Status State Counts" section unless further instructed by APDM's support staff. They are not necessarily indicative of a malfunctioning Opal or access point, and are often used just for debugging purposes.

Have more questions? Submit a request


  • 0
    Eyal Bar-kochba

    Understood. I'll try to reprocess the orientation without the magnetometer or rerun the test far away from any magnetic field.  It does look like that the magnetic field was oscillating correctly with the fan and didn't suffer any long term drift.


    Regarding the error state, it looks like it's due to the sampling rate that was configured (512 Hz).  Once I reconfigured to 128 Hz, it went away.

Please sign in to leave a comment.