Configuration → Device
The changes you make here will become effective immediately.
To lower the wear on the flash chips used to store the configuration data, changes are saved 10s after the last modification - or if the oldest unsafed data becomes 60 seconds old. In other words: If the power fails under heavy editing, you should never lose more than the last minute.
To give you an indicator when it is safe to power down the device, you can activate this setting. Whenever there is unsafed data present, the status LED will flash with a 100ms period (for a visual aid see the frontpanel section).
Some people like beating status LEDs to know that a device is still alive, others tend to become nervous if they see a blinking light. Chose your personal favorite behaviour for the controller's status LED when idling.
When active, all three status LEDs blink in a 1Hz interval to help you identify the device in a rack.