The GHK12X2 controller has a keypad lockout option to help prevent unauthorized modification of the controller operation. The factory setting for this lockout option is OFF. This application note describes the operation of the LOCKOUT OPTION.

The LOCKOUT CODE is the number code entered to engage or disengage the LOCKOUT OPTION. To enter the LOCKOUT CODE press menu once followed by the following number keys: 5, 6, 2, and 5. This will cause the controller to flash the following display: Lout/Lockout selection. The Lockout selection of YES will engage the LOCKOUT OPTION and NO will disengage the LOCKOUT OPTION. Pressing the 1 key will toggle the selection. When the desired option is displayed press the ENTER key.

When lockout is engaged only certain keys on the controller will function. These keys allow for information about the greenhouse environment to be viewed but not modified. The keys are as follows:

The Hot Keys function as normal to allow for viewing of the minimum and maximum temperatures, resetting the minimum and maximum temperatures, changing the zone being viewed, viewing the currently on outputs and viewing the stats. These keys all function normally according to the GHK12X2 Users Manual.

The Menu Key operation is slightly changed when Lockout is engaged. Pressing menu once will cause the normal response, which generally displays rSEt, unless under an alarm or fail condition. However while Lockout is engaged any key press other than the LOCKOUT CODE will return the controller to normal running operation. The LOCKOUT CODE is described above.

While the lockout is disengaged any keypad press will function normally.