You can set the iPad to never automatically turn off by configuring the auto-lock feature.Use this feature when you enable online ordering to ensure you receive online orders, or to ensure the iPad remains on during operating hours. When you set auto-lock to ‘Never,’ connect the iPad to a power source to keep the device charged. Additionally, manually power off the iPad, when you close the restaurant, for the iPad to fully charge.
Select Settings > General > Auto-Lock.
Select Never.
Press the home button to exit the Auto-Lock screen and return to the home screen.