Data acquisition and control system

Data acquisition and control system

Facilities

The tunnel’s data adquisition and control system is an essential part of the facility. It is used both for the control and regulation of the various ventilation systems, and for the acquisition and recording of data and images during testing.

Its key features are:

Structure

It is a decentralised system based in 13 Monitoring and Control Stations located in the service shaft and spaced every 40-50 m, as well as two units to control the ventilation stations. All the units communicate with the central control station through a closed fibre optic loop.

Input signals

Each Monitoring and Control Station recognises the following input signals to connect to the sensors and other recording units (video cameras, etc.):

  • Analogue input: 56 analogue inputs for the connection of external sensors (the number of inputs can be increased if necessary). The inputs can be configured to recognise any of the following types of signal and range:

    Tension

    +/- 80 mV/10 MΩ, +/- 250 mV/10 MΩ, +/- 500 mV/10 MΩ, +/- 1 V/10 MΩ, +/- 2.5 V/100 kΩ, +/- 5 V/100 kΩ, 1 – 5 V/100 kΩ, +/- 10 V/100 kΩ

    Intensity

    +/- 10 mA/25 Ω, +/- 3,2 mA/25 Ω, +/- 20 mA/25 Ω, 0 – 20 mA/25 Ω, 4 – 20 mA/25 Ω

    Resistance

    150 Ω/10 MΩ, 300/10 MΩ, 600 Ω/10 MΩ

    Thermocouple

    K, E, N, J, K/10 MΩ

    Resistance thermometer

    Pt-100, Ni-100

  • Digital input: 16 inputs (can be increased if necessary) for all-or-nothing signals from volt-free contacts.
  • Data links: The Monitoring and Control Stations recognise data inputs delivered through the series type interface RS-422/485 (4), or Ethernet links 10/10 BaseTX RJ-45 (4) supported on network TCP/IP using MODBUS protocol.

Actions

Each Monitoring and Control Station has the following outputs for control and regulation actions:

Typenº *Range or type accepted

Analogue

8

0 – 10 V, +/-10 V, 1 – 5 V, 4 – 20 mA, +/- 20 mA, 0 – 20 mA

Digital

16

Switching relays (max. 500 mA a 24 VCC)

(*) Standard number of outputs, can be increased if necessary

Data transmission

The Monitoring and Control Stations communicate with the central station through a fibre optic trunk system (100 Base FX) in a closed loop at 100 Mbps, TCP/IP MODBUS protocol. There are additional, free fibre-optic lines in the loop for any other use or equipment which might require it.

Central control station

A redundant system based on two independent computers connected via the local network, with a continuous power supply of 6 KVA. For the presentation and archiving of data, a type of SCADA software is used (iFIX professional).

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