A control system for a hydraulic servomotor (13) is disclosed. The control system comprises an electro hydraulic actuator (2) comprising a number of valves (9, 10, 11, 12, 18) for controlling fluid flows, a main control module (1), and one or more connectors. The control system further comprises at least one extension control module (3) comprising one or more connectors. Finally, the control system comprises means (6) for communicating signals between the main control module (1) and each of the extension control module(s) (3). Since the main control module (1) and the extension control module(s) (3) are able to communicate signals, it is possible to provide signals to/from the main control module (1) via an extension module (3), thereby in effect providing additional connectors to the main control module (1). Thereby the main control module (1) may be able to perform additional functions as compared to similar prior art control modules.