Thank you for your question,
PIN5 (Digital Input 1 - Ignition) of FMB120 is used to determine the status of vehicle's ignition, the device goes to sleep depending on configured ignition source, which can be:
- Power Voltage
- Engine RPM
If required you should connect the Digital Input 1 in order to monitor the status of the ignition, which will be used for "Sleep Mode" scenarios.
Please note that sleep modes are activated only when all of the conditions are met.
Please follow up on more detailed information on the available sleep modes in our wiki:
Hope this helps,