While historically, PLCs might have been thought of as “simple machine control,” today’s complex applications speak to the increasing sophistication of PLC/PAC technology as well the rapid growth in the discrete and hybrid marketplace. One such example is the use of over 300 Emerson PACSystems™ controllers in the tunnel ventilation, building management and energy reduction of 21 underground stations for a metro rail system in a major Asian city. The agency provides daily ridership for two million people across a 200+ mile network. Of course, safety and high availability are critical to operations. In addition, the agency continuously strives to achieve sustainable energy, meet government mandates and reduce energy costs throughout the system. In order to achieve these goals, the agency needed to control and visualize energy data from all of its high energy-consuming subsystems, such as escalators, elevators, and electrical and mechanical devices like pumps and HVAC systems. It also needed to be able to rapidly measure and compare energy consumption metrics across the fleet in order to provide immediate actionable energy conservation insights.
The agency selected Emerson to provide control infrastructure for 21 underground stations connected to a central control room in the center of the city. The scope of the project included design, implementation, commissioning and programming for the control and instrumentation solutions. Emerson provided 300+ PACSystems family controllers, including PACSystems RX3i PLCs, and SCADA for the solution. The solution was redundant across each station – located in the fore and aft of each – to mitigate any loss of control or view in case of emergencies.
The system controls and visualizes data from disparate subsystems like the tunnel ventilation fans, fire system, escalators, elevators, electrical and mechanical systems, access control, plumbing and other systems. The system is programmed to work automatically in various daily operations and emergency modes and ensure fire control and speedy evacuation of smoke in case of emergencies. PACSystems controllers integrate easily with third-party devices and controllers, supporting different protocols across the infrastructure to provide a unified control and HMI infrastructure. Station operators and central control room operators have a single control and visualization platform and the ability to respond immediately to maintain safety-critical operation. The HMIs have a 3D layout, are interconnected and have an extremely user-friendly design that helps operators visualize the layout and immediately open the display of any area at the click of a mouse. The data from each station is historized in a central historian and helps derive actionable insights related to operator errors, equipment failure and operational status of different subsystems.
At the same time, the agency wanted to optimize the control infrastructure of its network in order to achieve the first-of-its-kind energy management solution in the country. Energy meters were installed at all monitored machinery and data and is routed to PACSystems™ RX3i PLCs. The data collected from individual machinery is displayed on dashboards located at each station, as well as at a central energy monitoring control room. The centralized data allows comparison of energy consumption from similar equipment and machinery in different stations. In addition, the system performs complex calculations to determine abnormal energy usage and displays it in a graphical “heat map” format. This ability to monitor real-time energy and compare it across stations helps the agency detect anomalies early and take corrective action to keep consumption in check. In addition, the trends and analysis allow operators to keep a digital log of equipment health, manage equipment warranty benefits, detect equipment failures early, and make operational changes to further reduce power consumption. The PACSystems single-point solution helps the agency meet sustainability targets and allows continuous improvement of energy efficiency throughout the metro rail operation. Ultimately, the project won premium certification by their governmental green building council and set new standards for energy sustainability for all metro rails in the country.
Even since this world-class installation, PLC technology has advanced to such an extent that any user of machine-level systems needs to investigate the newest developments in PLCs to help solve problems of workforce, supply chain and profitability. It’s worth the exploration.
Check out these two case studies in full:
- Metro Transit Agency Employs PACSystems™ Solutions to Operate 21 Underground Stations in an Infrastructure Critical to Human Safety
- Leading Transit Agency Uses PACSystems™ Solutions to Achieve Energy Efficiency Certification