INTEGRATED SOLUTION FOR THE AUTOMATION OF A HYDRAULICS LABORATORY João Palma 1 , Armando Cordeiro 2 1 Laboratório Nacional de Engenharia Civil, CPCE Av. do Brasil, 101, 1700-066 Lisboa, Portugal. E-mail: jpalma@lnec.pt 2 Escola Superior de Tecnologia, Instituto Politécnico de Setúbal Estefanilha, 2914-508 Setúbal, Portugal. E-mail:acordeir@est.ips.pt Abstract: An automation structure devised for a hydraulics laboratory is presented. After a brief plant description and an analysis of the major automation requirements and constraints, the developed structure is presented. This structure consists of a core of industrial fieldbuses and PLCs for critical tasks involving safety and protection, namely of electromechanical power equipment control. Data acquisition is centred in PC platforms with data acquisition boards and IEEE 488 buses for special metrology equipment. The mass flow automated measurement is described as well as the corresponding HMI solution. 1. LABORATORY PLANT DESCRIPTION LEHid is a hydraulics laboratory recently set up in Lisbon, at Laboratório Nacional de Engenharia Civil (LNEC). The installation is devoted to hydraulics research, equipment testing and calibration, and consists of a hydromechanical arrangement with three pumps, more than 30 motorised valves and 100 mm to 400 mm diameter pipes (see fig. 1). It consists of two major sections: one provided with facilities for pump testing and the other having a set of equipment for mass flow measurement, as described in fig. 2. P1 to P3 are immersed rotor centrifugal pumps driven by three-phase induction motors with electronic variable speed drives. Motors in groups P1 and P2 have 115 kW mechanical output power each and 220 kW in group P3. Tanks 1 and 2 are equipped with load cells, rated to 30 tons and 3 tons, respectively. At the top of each tank there is a flow diverter used to direct the water flow either to inside the tank or to a bypass pipe. The diverters are key organs in the process of gravity flow measurement. They are actuated by three-phase induction motors (5.5 and 4 kW) and share a single electronic variable speed drive. Deflection time is less than 150 milliseconds. In this paper the main focus is directed to the flow measurement section. Fig. 1. View of flow measurement section of LEHid. 2. REQUIREMENTS AND CONSTRAINTS The major automation needs for this laboratory were: - closed-loop automatic control of flow and pressure by using variable speed pumps and needle valves, including starting procedures; - automated configuration of admissible hydraulic circuits by valve actuation; - automated test/calibration procedures (mainly for flowmeters), while keeping an adequate level of human assistance; - self-protection of equipment and personnel; - extensive system integration; - appropriate human-machine interfacing.