Garage Door Opener
Author: Shawn Modersohn <shawn@shawnmodersohn.com>
2023
License: Creative Commons V4 <https://creativecommons.org/licenses/by/4.0/legalcode.en>

Scope:
	This garage door opener application has a wall mounted push button and two remote push buttons.  The buttons are momentary.  There are two limit switches, one to stop the door at the top and the other to stop the door at the bottom.  There is also a safety photo eye three inches above the floor that when flagged will immediately stop the door from closing and it will begin to raise one second later.  There are to be forward and reversing contacts each with auxiliary inputs.  The motors shall not run without these inputs being sent to the PLC in a timely manner.
	If a push button is clicked the door will begin to open or close based on whichever limit switch is engaged.  If a push button is clicked during the door's motion the door will stop.  If it is clicked again during a stoppage in this manner it will reverse course respectively.  
	There is a convenience light that will energize for 5 minutes anytime a button is pushed. Lastly, be prepared to handle an initial install where it's possible that neither limit switch is engaged.