Calculate the number of hours of operation

[Benhalor]

In order to facilitate maintenance, display

• The number of hours the machine has been ventilating
• The number of hours the machine power has been ON

[dsferruzza]

This implies being able to:

1. count these durations
2. persist them on FS (across reboots)
3. display them on a Maintenance screen/modal

[valeriansaliou]

I guess this should be done from the firmware, written to its permanent EEPROM memory (it's like an "uptime" log, or a car's odometer), and then sent to the UI through the telemetry protocol (to be shown in a machine information box, which could also show the machine serial, more software build information, etc...).