Analysis of timing properties from network control systems

Due to the increased availability of low cost network technology, the use of networks to interconnectsensors, actuators and controllers is becoming widely accepted for the implementation of feedback controlsystems. Such type of feedback implementation, wherein the control loops are closed through a real-timenetwork, is called Network Controlled Systems (NCS). When implementing a NCS, the underlyingcommunication network must provide a timely communication service, which must be the adequate to fulfilthe control application requirements. Therefore, the assessment of the network responsiveness to the realtimerequirements of the control application is a fundamental issue. The CAN network is usuallyconsidered suitable to support small-scale NCS, due to their real-time capabilities. However, their temporalresponsiveness is highly dependent on both the timing characteristics of the supported message streams,such as its periodicity and the related message lengths. In this paper, we analyse the timing properties ofCAN control network. Basically, we assess their capability to support Network Controlled Systems,through the evaluation of the related worst-case messages response time. A small example of a NCS isthen used to assess the capability of the CAN control network to fulfil control application requirements