Abstract: A method for displaying state data of an industrial plant by a server communicating with a client over a network includes, in a first mode, receiving live state data from a data source and sending a portion of the live state data to the client for display into a graphical user interface. The method also includes, in a replay mode, reading stored state data from a data storage, the stored state data being stored at a storage rate, and sending a portion of the stored state data to the client for display into the same or a different graphical user interface at a replay rate, which can be different than the storage rate. The data source can include a programmable logic controller (PLC) and the live state data and the stored state data may represent any combination of sensor data, data derived from sensor data, control output data, control input data, and program state data.