Requirements and current state
Process steps, I/O, permissives and operating limits are defined. Temperature, pressure, level or flow requirements are assessed with sensors and actuators. Control logic is not copied between plants without reviewing their differences.
Technical design and development
PLC/SCADA sequences, parameters, trends and alarms are developed together. Loop behaviour depends on sampling, process delay and device limits. Data acquisition and real-time control have distinct roles.
Testing and implementation
Normal production, start, stop and fault scenarios are tested. Functional descriptions support operator intervention and maintenance handover. Process and functional safety requirements are scoped separately with qualified specialists.