loop diagrams , quality procedures , Preventive Maintenance, Sat, statutory requirements, Process Optimization, Plc, instrumentation failures, Industry 4.0, digitalization, plant automation performance, C I systems, instrumentation specifications, Calibration, SCADA, logic diagrams, Hmi, control philosophies, industrial automation systems, Safety Standards, Rca, Dcs, Troubleshooting, FAT, corrective actions