Automation system for Compressed Natural Gas Compressor. This compressor is used at retail distribution centres. A redundant CPU system is used for enhanced availability. PLC and HMI are mounted in a flameproof panel. HMI operation is done using inputs of external keys to PLC, mounted on the flameproof Panel. Online data, trends and alarms are made available on Central WinCC station (SCADA) for 5 Compressor which is on wireless GSM Network. Inlet gas flow and discharge gas flow is provided on local HMI as well as SCADA for observation. The flow meter communicates with PLC using Modbus RTU Protocol.