When an Adaptor Board not Found (AB) alert occurs, it means that a 72 or 96 station controller is not seeing, or registering the second adapter board, or chassis.  Irrigation will not occur until this is resolved. 

Some of the possible causes for this alert include: 

• The ribbon cable to the expansion board is not properly connected
  
  
• The secondary adapter has been damaged or has failed
  
  
• The command module was moved from a high station count controller (72/96) to a low station count controller (24-48)

Possible Fixes

Power down the controller and re-seat all ends of the ribbon cable and power back up.

If the problem is still not resolved, contact Customer Support for further troubleshooting.