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ICP DAS’s Controller for Railroad Switch Monitoring

ICP DAS‘s programmable automation controller (PAC) and I/O modules record the railroad switch motor’s current and voltage data. The software AVEVA Edge SCADA displays the real-time status and visualizes reports to build the railroad switch monitoring system.


In rail transport, switches play an important role in ensuring that trains move in the right direction. Usually, the control center is responsible for organizing trains and planning routes, and remotely controls the movement of the switch through the sign panel so that the train can move on the correct track. Since the system is controlled remotely, USCIENCE COMPUTER CO., the company that provides maintenance services for this system, according to the needs of the customer Taoyuan Metro Corporation, uses IoT technology to monitor the status of the switch to ensure its normal operation. This case illustrates the application of ICP DAS‘s smart solution for rail transport in the Taoyuan Metro System in Taiwan.

Switch monitoring system in Taoyuan metro

The Taoyuan Metro System (commonly known as the Taoyuan Airport MRT) is a rapid transit line that serves the Taipei and Taoyuan metropolitan areas and the airport transit line of the Taoyuan International Airport. The road network covers Taipei City, New Taipei City, and Taoyuan City, and it is the third MRT system in operation in Taiwan. In order to improve the safety of the MRT system and reduce the failure rate of switches, Taoyuan Metro has implemented ICP DAS‘s solution to monitor the railroad switches.

This solution reads and stores relevant switch data and provides alarm, data analysis, and output functions. It also provides relevant information about each station to management personnel for instant control of the overall situation in the field or in the control center.

Railroad switch

ICP DAS’s railroad switch monitoring solution

In this case, ICP DAS’s railroad switch monitoring solution can be divided into two parts: the rail control center at the station and the railroad tracks in the route network. On the side of the control center monitoring system, ICP DAS provides AVEVA Edge SCADA software for real-time dynamic and visual reporting, monitoring the motor’s current and voltage changes of each switch, the voltage of each detection point, and the number of turns. On the side of the railroad tracks, the WP-8821-CE7 programmable automation controller, I-8017HW-G analog signal input module, I-8046W-G digital signal input module, and I-8064W-G power relay module are used to record the current and voltage of the switch motor, as well as operating time, starting current, and average current. The system architecture is as follows:

System architecture diagram

The I-8017HW-G is a high-performance analog signal input module that can be used to measure voltage and current. In this case, it is used to obtain the switch motor voltage and forward/reverse current information.

The I-8046W-G is a 16-channel digital signal input module used for long-distance measurement. The effective distance for dry contact connection is up to 500 meters. In this solution, this module collects the forward/reverse signals and captures the track positioning signal detected by sensors located in front and behind the switch. With the I-8064W-G 8-channel power relay module, users can monitor the conduction status of the dry contacts of the relays connected to the switch.

The WP-8821-CE7 programmable automation controller uses the Windows CE 7.0 operating system and has the characteristics of fast real-time data processing, thus performing as a switch data logger in this case. In addition to recording information such as the current and voltage of each switch to ensure the smooth operation of the motor, it calculates the operating time of the switch and transmits the track field data to the rail control center through the Modbus TCP communication protocol through an optical fiber.

The monitoring system of the control center uses the AVEVA Edge graphic control software to present three categories of screens: real-time data screen, accumulated data screen, and chart data analysis pages with icons. In addition to displaying the real-time station connection status and the status information of each monitoring point in the route chart, the real-time data screen also shows the current, voltage, and power waveforms on the monitoring screen for the convenience of management personnel for analysis. Threshold parameters can be set in the system’s alarm management mechanism to indicate abnormal situations.

Real-time data screen
Waveforms circuit


  1. With long-term monitoring, maintenance personnel can analyze and evaluate the data and effectively determine the root causes of switch failures, thereby reducing the chance of occasional failures and achieving planned and preventive maintenance goals.

  2. Since railroads belong to the outdoor high-voltage power environment, the electronic equipment used on them must be resistant to high temperature and humidity, and also must have an electromagnetic interference prevention mechanism. All ICP DAS‘s products provide electromagnetic interference (EMI) and high/low temperature testing. Thus, the stability and safety of controllers and I/O modules assure customers that the equipment used in the system is efficient and safe.

  3. The WP-8821-CE7 programmable automation controller has a built-in redundant power input port, which can be connected to a redundant power system (RPS) or uninterruptible power system (UPS) to ensure that the motor monitoring of the switch can continue to operate and is not affected by a sudden power failure.

  4. The WP-8821-CE7 PAC provides eight I/O expansion slots to save space, and management personnel can adjust functions according to the actual situation in the field to meet different needs.

  5. The chart data analysis page provided by AVEVA Edge can be used for early warning analysis before equipment failure occurs. According to the boundary conditions proposed by the customer, including the time duration that the switch takes to reach the correct position and the peak value of the measurement after the start. When the data goes beyond the boundary conditions, the system will send warnings to remind the track maintenance personnel to perform preventive maintenance or equipment replacement.

ICP DAS’s controllers:

ICP DAS is dedicated to developing controllers for various industries, which can be divided into two groups: programmable automation controllers (PAC) with an open operating platform and IIoT controllers with simple operation and no programming required. The first group includes 8000 and 9000 series programmable controllers. The second group includes WISE series edge controllers, PMC and PMD series power meter concentrators, and UA series communication servers.

ICP DAS‘s programmable automation controllers support different communication protocols and work with various operating systems, including Windows, WinCE, Linux, and others. They are highly suitable for applications in complex environments or complicated logical operations like traffic flow monitoring , railroad signal monitoring, vaccine cold storage monitoring, and wind/solar energy storage monitoring.

IIoT controllers developed by ICP DAS meet the requirements of industrial IoT edge computing, environmental monitoring, and communication between various devices in the IIoT network.

ICP DAS‘s WISE IIoT edge controllers support both wired and wireless communication (3G/4G), and are widely used for logic control and monitoring in various industrial applications. The built-in IF-THEN-ELSE statement can execute automation logic stably and efficiently. It also provides functions for mathematical operations, scheduling, and sending email notifications.

PMC/PMD series power meter concentrators can be connected to ICP DAS‘s smart power meters via RS-485 or Ethernet. Thus, they can read and record the energy consumption information measured by the smart power meters in real-time. The UA series communication servers allow users to connect the front-end devices to the cloud, link IT to OT, link cloud and web apps, and integrate the cloud-based Internet of Things (IoT).

ICP DAS‘s IIoT controllers also support the following functions:

  1. Variety of network connection methods. In addition to Ethernet (Modbus TCP communication protocol) and RS-485 (Modbus RTU communication protocol), data can be transmitted via the MQTT communication protocol to the cloud monitoring software through encryption.

  2. Variety of real-time alerts. When the equipment does not work correctly, a real-time alert can immediately send a notification to the management personnel (via email, SMS, LINE, WeChat, and others) to solve problems promptly.

  3. The built-in if-then-else statement of WISE, PMC, and PMD series devices can execute automation logic stably and efficiently.

  4. In case of an interruption in communication, missing data can be filled in to ensure no data is lost.


The ICP DAS‘s solution for monitoring railroad switches shows the status of railroad switches in real-time with visualized reports, helping maintenance personnel to instantly monitor the situation on the track, perform preventive maintenance and reduce the cost of subsequent maintenance. In the event of an emergency, maintenance personnel can immediately troubleshoot the problem to ensure traffic safety.

The products provided by ICP DAS have long earned success and trust from customers. The company’s team clearly knows that only stable and secure equipment for data collection and communication can become a reliable foundation for intelligent IoT solutions and create great value for various industries.

Related products:

WP-8821-CE7 8-slot Standard PAC with Cortex-A8 CPU and WinCE 7.0
I-8017HW-G 8/16-ch Analog Input Module
I-8046W-G 16-ch Isolated Digital Input Module
I-8064W-G 8-ch Power Relay Module

ICP DAS View All

ICP DAS was established in 1993 and strongly focuses on innovation and the enhancement of industrial automation technology. ICP DAS continuously endeavors to develop a comprehensive selection of products ranging from remote I/O controllers, distributed I/O modules, I/O data acquisition boards, programmable automation controllers, industrial communication modules, web-related products, motion control systems, SCADA/HMI software to automation solutions for applications critical to energy management, motion automation, smart factories, intelligent buildings, and smart cities. Our ambition is to provide a wide range of high-quality products and versatile applications, together with prompt and efficient services, that can be implemented to assist in the continued success of our clients worldwide.

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