A method is provided for teaching a transfer robot used in conjunction with a workpiece processing system including a pedestal assembly, a light sensor having an optical input fixedly coupled to the pedestal assembly, a transfer robot having an end effector, and a processing chamber containing the pedestal assembly and light sensor. The method includes the steps of producing light within the processing chamber, moving the end effector over the optical input such that amount of light reaching the light sensor varies in relation to the position of the end effector, and recording the signal gain as the end effector is moved over the optical input. The method also includes the step of establishing from the recorded signal gain a desired position of the end effector relative to the pedestal assembly.