Power Module


The Power Module should always be connected to the Mainboard powerless.
If it is connected powered on the Mainboard may not boot because of the voltage timing requirements.

Power Module fan

The module contains a PWM-controlled Noctua fan.
The fan is controlled by the Power Module or the Mainboard when the fan control service is active.
It cools both the Mainboard compute module and the Power Module itself based on a calculation of multiple temperature sensors.
It is not necessarily required for ambient temperatures <50°C, but improves the computing performance of the Mainboard and the service life of the Power Module.
If the measured fan speed is lower than the expected value, the fan is most likely not connected, stuck or defective.
It must be replaced as soon as possible to achieve the specified operating temperature range and performance!

Power Module fan maintenance

The Power Module has a fan which requires maintenance.
Despite the fact that the module may only be used in low-dust environments, dust may accumulate in the housing over time.

This must be checked every 12-24 months.

To do this, shut down the system and disconnect the power module from the mains voltage.

Remove the module from the mainboard. It is not necessary to disassemble the module.

Use a vacuum cleaner to remove dust from the ventilation slots.
Clean the ventilation slots of the Mainboard at the same time.

Power Module error counter

The Power Module continuously measures all supply voltages, currents and temperatures in order to detect faults.

If a limit is exceeded operation can not be guranteed and the Power Module hard resets the system.

It tries to write the cause of error into its storage. In some cases (hard shortcut on 12V rail) it may not be able to save the error.

If the error counter increases in a short period of time, you should check

  • the AC input voltage (cheap UPS may cause this)
  • the connections of the IO module
  • the ambient temperature for issues.

You can view the counter via console on the device:

curl http://localhost/api/power/1.0/1/protectionlog

You can reset the counter via console on the device:

sudo systemctl stop nexus-drv-power
echo -en "\x01\x03\x06" > /dev/slot1
sudo systemctl start nexus-drv-power
Label Led On
top (AC connector side) Power delivery: <= 100.0% (30W)
Power delivery: <= 87.5% (26.25W)
Power delivery: <= 75.0% (22.5W)
Power delivery: <= 62.5% (18.75W)
Power delivery: <= 50.0% (15W)
Power delivery: <=37.5% (11.25W)
Power delivery: <= 25.0% (7.5W)
Power delivery: <= 12.5% (3.75W)