A method and a device in connection with an actuator intended for use in connection with a fluid flow or fluid reservoir, in particular an actuator that is designed to be used in connection with a drainage pipe for the production of oil andor gas in an oil andor gas reservoir. A method for operating the device involves sensing the environmental characteristic to provide a measured value, and defining a desired maximum amplitude of variation within which the measured value may vary. Accordingly, a reliability of a data recordingreproducing with respect to the optical disc is improved. After obtaining the initial diagnosis, the system determines the test patterns to be printed and the image quality tests to be performed. In some embodiments, the output voltage of the pump may be stepped in response to program loop iterations during a program operation, or set to a target voltage during an erase operation. The electrical characteristics of the MMIC chip can be evaluated without an increase in bonding pad capacitance.