A computer based control system including a field network to which field devices equipped with hardware addresses and logical names are to be connected, a control device performing addressing control in relation to the field devices and their logical addresses and a simulation handling device. The simulation handling device has an own logical address, an own hardware address and is capable of obtaining a logical address, as well as possibly a logical name and/or a hardware address of at least one field device involved in the simulation. It notifies the control device that the field device is connected to the field network, detects a control signal directed towards field device addressed using the logical and/or hardware address of this field device and responds to the control signal with simulation results using the same logical and/or hardware address as the source of the response.