A Monitoring and Diagnostics System is provided, which includes a monitoring unit and a monitored unit remotely located from the monitoring unit. The System also includes communication means between the monitoring unit and the monitored unit. The monitored unit includes data acquisition means for providing fault data of the monitored unit and the communication means are adapted to communicate the fault data from the monitored unit to the monitoring unit. The monitoring unit includes a rules engine having a set of expert rules for analyzing the information contained in the fault data and being adapted to deduce diagnostics information from the rules and from the information. In addition, a communication method for communicating between a first Programmable Logic Controller and a second Programmable Logic Controller or a central unit is provided, in which a description file is provided.