The line is 13.7 km long (5.9 km of which in tunnels, 4.8 km in indoor trenches, 1.3 km on the surface and 1.7 km on flyovers) and to date includes 17 stations, plus a depot.
The SCADA system acquires, collects and processes data from peripheral PLCs divided into three categories (IA, ITA and Ventilation), located in each of the seventeen stations plus the depot. All the collected data is stored centrally and is made available to operators who deal with the carrying out and maintenance of the subway line.
The IA PLCs deal with managing the Power plant signals, the ITA PLCs deal with managing the Auxiliary Technological plant signals (escalators, elevators, pumps, burglar alarm system, fire prevention system...), while the Ventilation PLCs deal with managing the station, tunnel and technical room ventilation system signals.
The system has all the typical main characteristics of a SCADA system, and therefore manages the following functions:
- Graphic interface for global and detailed management of the system
- Alarm life cycle management
- Event management (in terms of configuration, visualization, printing and storing)
- Command management
- Information storage and trending
- Configuration of access levels and user privileges
- Function status of all equipment in the SCADA network
- Redundancy management.
In particular, the SCADA system allows the operator to monitor and supervise the stations' peripheral equipment from the Central Operational Post (PC), providing all the status and alarm information and permitting the issue of commands that are necessary to manage the equipment. This peripheral equipment refers to the subsystems of:
- Electrical power plants (electrical substations, MV/LV transformation cabins, UPS power units...)
- Auxiliary technological systems (fire prevention and burglar alarm systems, water pumping systems, passenger movement systems, heating, station gates, electrical power generators, lighting systems...)
- Ventilation systems (technical, station, tunnel and emergency ventilation systems, air barriers, fire doors...).
This goal has been achieved by using RTUs (Remote Terminal Units) comprising hardware (PLCs, I/O boards...) and software for station equipment management.
The SCADA system mainly has the task of visualizing all the field information in graph format, and sending commands decided by the operator, but not of making autonomous decisions and automatically sending commands further to detected events. An operator's intervention is always required, but it is possible to propose and manage command sequences, which require a simple confirmation.
Although verification of the consistency of the commands and safety of the maneuver is the responsibility of the controlled system, software filters are provided for which, based on the information coming from the system. prevents a command from being sent if it cannot be realized (e.g. opening switches already open, or start up of escalators that are already working).
In order to guarantee a high level of reliability for the SCADA system as a whole, and in particular as far as the critical systems, such as emergency ventilation and fire detection, are concerned, the SCADA system has been designed with redundancy characteristics.