Apart from HMIs , PC based Systems which are popularly known as SCADA Systems are available from SIEMENS. Complete plant equipments can be visualised and operated from the Computor screen. Monitoring , recording and reviewing of the functions and events are possible with SCADA System. Alarms and faults can be monitored on real time basis. Trends of parameters like pressure , flow, Temperatures , etc.can be continuously recorded and can be reviewed whenever required. SCADA System serves as an excellent tool for monitoring and recording of critical process parameters.