Synchronization in a force measurement system using EtherCAT

This paper addresses synchronization between master and slaves in a force measurement system using EtherCAT. One property of the system is that the operation of the measurement controller is strictly bound to the operation of the measurement nodes and not vice verse. The measurement nodes generate data in a cyclic fashion and the controller must fetch the data in each cycle. Two issues arise here. First of all the latency must be kept low to meet the overall target on step response time for the system. Secondly the communication must be robust, i.e. the controller is not allowed to miss data. This may happen due to jitter in the controller operation. This paper suggests a controller design based on a so called internal EtherCAT slave to strictly bind the operation of the controller to the operation of the measurement nodes.