The unit power management settings on the mobile device template controls the power management functionality of the mobile device.
These settings impact the mobile device as a whole and it is important to note that once the device has been turned off or shut down with these settings, all other power related setting will no longer take effect. In other words, switching the mobile device off with these settings also switches off all peripheral devices and stops any further peripheral surfacing from happening.
Unit power management logical device settings are available on the MiX 4000 and MiX 6000 mobile devices.
- Click Manage.
- Under Config admin, click Templates.
- Click the Mobile device templates tab on the left.
- Open the relevant template by clicking the green hyperlinked template name or the actions arrow and select Edit.
- Click on the mobile device type link to access the mobile device properties:
- Scroll to the Unit power management section (only available on MiX 4000 and MiX 6000 devices).
- Enter the settings as explained below.
- Click Save.
The Turn mobile device off when battery voltage falls below (mV) default value is 11500. This setting allows a lower vehicle battery voltage limit to be specified in mV. This feature stops the mobile device from completely draining the vehicles battery if the vehicle is parked for an extended period of time. The threshold should typically be set to a voltage that ensures there is still enough energy remaining in the battery to restart the vehicle at the beginning of the next trip.
When the lower voltage threshold is reached, the firmware will allow a 15 minute period to confirm that the voltage is indeed below the threshold before shutting down the device. It is unlikely that this limit will be reached while the vehicle is in trip as the alternator would typically be maintaining a higher voltage on the vehicle battery to charge it while the engine is running. If, however there is a fault with one of the vehicle systems and the battery voltage drops below this level during a trip the mobile device will only shut down once a 15 minute timer has expired and that trip has ended, assuming there are other sources keeping the unit in trip i.e. wired ignition, acceleration, speed, RPM.
NOTE: If there is not going to be an automatic shutdown of mobile device time configured after trip end (see setting below) then it is recommended that a conservative voltage setting be selected for this low battery voltage setting. A typical lead acid battery is considered to only have around 40% or its capacity remaining at 12V and this can restrict its capability of providing the cranking current required to start the vehicle. This problem is made even worse at lower temperatures where the batteries capacity is already reduced.
The Automatic shutdown of mobile device checkbox and associated Turn mobile device off when asset is parked for more than settings allow a forced shutdown at a fixed time after the end of the last trip. The settings here will depend on the particular application and requirements for out of trip data but should be set up so that, should a vehicle remain out of trip for an extended time, the vehicles battery still has sufficient energy to ensure reliable restarting when the next trip occurs as explained above.
NOTE: Once this time has elapsed the mobile device shuts off onboard modules as well as external peripherals and no further surfacing will take place either, regardless of what settings are configured in the peripheral power management section. The GPS module can be expected to shut down as soon as this time expires but the external peripherals powered from the positive drive connection may take a bit longer to power down.