To configure the OpenFlow controller settings on the Zodiac GX  go to System->Startup on the left-hand menu in the web UI. At the bottom of the startup page, you can find a listing of the rc.local file which contains the configuration settings for Open vSwitch. There are two settings (see below) that you need to change for your OpenFlow controller, they are IP_CONTROLLER_1 which is the IP address of your OpenFlow controller and PORT_CONTROLLER_1 which is the TCP port your OpenFlow controller is listening on.

Change these two settings to the required values and then press Save & Apply at the bottom of the page to save these changes, then reboot the device to apply the settings. If there is an issue perform a factory reset by pressing and holding the reset button for 20 seconds and then release and allow the device to restart. This will restore the configuration back to the default settings and allow you to again connect to the device.

To set multiple OpenFlow controllers, add a second set of controller variables and add the variables to the set-controller line towards the bottom of the file, in this example IP_CONTROLLER_2 and PORT_CONTROLLER_2 have been added. 

A copy of a 2 controller config file is attached for reference which you can cut and paste into the box as a starting point.