A method of generating a heartbeat signal for an application comprising one or more objects that may enter a halt state is described. The method comprises: sending a status request to a defined interface on each object; and monitoring responses to the status requests to ascertain if each object is operating normally or in a halt state. The method further comprises: generating an application valid signal in the event that each object is operating normally; transmitting the application valid signal, if generated, to a monitoring component independent of the application; and generating at the monitoring component a heartbeat valid signal in response to receipt of the application valid signal.