Power Distrubutor uses Active Remote I/O with Linux-based Embedded Computer for Real-Time SCADA System

InTek is a SCADA system integrator and developer of real-time SCADA systems for the Asia power distribution market.

Conventional SCADA systems are typically RTU-based. The SCADA RTU must be physically wired to each relay and protection relay. Therefore, the wiring is complex and not flexible. Status control and measurement is limited to the hardwire and transducer. Moreover, fault recording is not really possible.

Thanks to the networking features of MOXA's UC-7420 and ioLogik E2210 Active Remote I/O, InTek was able to greatly reduce wiring costs while gaining far greater system flexibility than before.The UC-7420 and ioLogik E2210 allowed administrators to remotely monitor physical I/O devices, such as relays, over the Ethernet network. Using the powerful, built-in Linux platform of the UC-7420, InTek implemented multiple protocols, including IEC60870-5-104, 101, DNP3.0, Modbus/RTU, and ABB SPAbus. The UC-7420 was thus able to serve the role of a high speed, network-based RTU in the application.

Benefits of ioLogik E2210 Active Remote I/O Server:

• High-speed Active Remote I/O messaging provides I/O data in real-time
• Fewer host computer resources are used
• Click&Go Logic provides condition-based I/O messaging
• Modbus/TCP provides overall I/O status polling

Benefits of UC-7420-LX Embedded Computer:

• Dual LAN ports make it easy to set up redundant distributed networking system
• 8 RS-232/424/485 serial ports allow the connection of diverse equipment
• Included Linux development platform is easy to use
• Low power, fanless design offers high stability and reliability for long operational life
• Wide power input range satisfies system demands

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Vanguard International Semiconductor Corporation is a large specialty IC foundry in Taiwan that offers a range of process technologies. The products produced by Vanguard include a wide range of ICs, such as 0.18 mm logic, mixed-signal, analog, high voltage, low power, CMOS RF, Flash, embedded memory, and bipolar CMOS DMOS (BCD) ICs. One of Vanguard's Taiwan plants produces an average of 55,000 8-inch wafers each month.

The semiconductor manufacturing process involves many chemicals and gases, some of which are extremely toxic. Gases must be carefully monitored and controlled to ensure the safety of plant workers and the people living in the vicinity of the plant. Data collected while monitoring is also used to prepare environmental reports for local and government monitoring agencies. Vanguard needed an extremely reliable network to collect and transmit all monitoring data to the plant's monitoring and control center. The network must be extremely reliable, with non-stop operation and quick recovery after failures.

System Description

Vanguard's plant uses a combination of continuous monitoring gas monitors to detect toxic gases, such as ammonia, oxidizers, hydrides, mineral acids, hydrogen cyanide, hydrogen sulfide, and PFCs. The monitoring is done using CM4 gas monitors and System 16 gas monitors (four CM4 monitors combined), and gas cabinets that collect parameters such as temperature and barometric pressure. The gas monitors use digital signal data and special Chemtapes to detect leaks in a matter of seconds. The complexity (the number of different gases that need to be detected) of a given location dictates the level of monitoring that is required. The locations are usually scattered throughout the plant, which means that distance, speed, reliability, and safety factors related to operating in a hazardous environment factor heavily into the network configuration.

Vanguard chose a combination of MOXA products that includes several UC-7408 data acquisition embedded computers for remote communication with their SCADA system, and EDS-508-MM-CC 8-port managed Ethernet switches for the fiber backbone and communication between devices. EDS-508 switches are Class 1, Div. 2 certified for use in hazardous environments that contain volatile flammable liquids, gases, or vapors. The EDS-508's Turbo Ring feature supports a scalable, extremely reliable, always-on, high speed fiber backbone that supports quick recovery and long distance data transmission. Monitoring data is collected from throughout the plant and then transmitted to the central monitoring center in real time, allowing for more reliable and efficient monitoring and data collection.

Business Benefits from MOXA

• Under 300 ms Turbo Ring recovery time and relay output protect network in the event of system failure
• EDS-508 switches are Class 1, Div. 2 certified for use in hazardous environments.
• UC-7408 switches are Real COM+ enabled
  - Remote communication and Real COM emulation
  - Multi-host connection for redundant SCADA
• EDS-508 switches can send a warning via e-mail or relay output for user-configurable exceptions, providing system managers with real-time alarm messaging.
• EDS-508 switches support two power inputs for increased reliability.
• EDS-508 switches offer superior reliability with fanless design and high MTBF rating.

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KLA-Tencor, the world's leading supplier of process control and yield management solutions for the semiconductor and related microelectronics industries, chose the MOXA UPort 1410 4-port RS-232 USB-to-serial hub for its new Optical Surface Analyzer (OSA).

The Candela 5100 System combines five independent detection methods: scatterometry, reflectometry, ellipsometry, optical profilometry, and kerr effer microscopy into one compact system. The measurements made by the OSA system play a significant role in semiconductor manufacturing for production monitoring, process development, and surface analysis. Due to the compact size of the system, KLA-Tencor selected MOXA旧 UPort 1410 USB-to-serial hub to enable the Candela 5100 to monitor different types of testing machines simultaneously.

KLA-Tencor was particularly interested in two key features of the UPort 1410. Its support for true high-speed USB 2.0 transmission helped make KLA-Tencor's products more future-proof. Another important feature was the innovative COM Preserver? provided on all UPort series products. Most USB-to-serial hubs assign COM port numbers automatically each time the hub is plugged into a USB port. Typically, the COM port settings change each time the USB device is unplugged and then plugged back in. KLA-Tencor was looking for a solution that would retain the COM port settings wherever and whenever the hub was plugged in. MOXA旧 UPort serial hub provided this feature with COM Preserver? When the UPort is unplugged and then plugged back in, it is not necessary to re-install the driver and reconfigure the COM ports, since COM Preserver?does this automatically.

KLA-Tencor is now ranked as the number two supplier of manufacturing equipment in the semiconductor field. The Candela 5100 OSA system scans the entire disk surface, and the data is displayed as a highly detailed image map. The scan area and lateral resolution are user-definable, permitting high resolution zoom scans in specific areas of interest. With its built-in scriber, defective locations can be marked automatically for future reference.

Semiconductor Manufacturing Diagram:

Copyright © 2006 KLA-Tencor Corporation.

UPort 1410 provides these advantages:

• Support for high-speed USB 2.0, up to 480 Mbps
• Serial transmission speed up to 921.6 Kbps
• 128-byte FIFO and on-chip flow control
• Built-in 15 KV ESD protection
• IP30-rated, rugged metal casing
• Retention of COM port assignments across different PCs
• Mini-female-DB9-to-terminal-block accessory for easy wiring
• Support for both bus power and external power

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RS-232/422/485 serial devices are used around the world as integral components of industrial automation systems. This is because the RS-232/422/485 interfaces are well-known for being economical and easy to use. The 2-wire RS-485 interface may be used to connect up to 32 serial devices to a single half-duplex line, which may be up to 1200 meters in length. If more devices or greater distances are required, RS-485 repeaters may be used to extend the 1200 meter limit, increase the number of devices connected to the system, or set up a distributed tree-type network (not supported by the RS-485 standard). However, RS-485 repeaters cannot be used to extend the transmission distance up to several kilometers. Furthermore, the repeaters cannot be used to prevent the serial signal from being corrupted by electromagnetic interference. One way to overcome these problems is to use fiber optic communication to convert the serial signal to a fiber signal.

MOXA旧 TCF-142 series of serial-to-fiber media converters are designed to extend the transmission distance of serial devices that are part of an industrial automation network. Models are available for both multi-mode (M-models) and single-mode (S-models) fiber with ST connectors. The optical fiber links can be up to 2 km for multi-mode models, and up to 20 km for single mode models. Users are always happy to learn that MOXA旧 TCF-142 media converters require little if any configuration. Since the media converter simply transforms the communication signal from one format to another, the TCF-142 does not have a baudrate to configure. The only step the user must take before switching on the device is to configure the serial interface. In addition, when connecting the TCF-142 to an RS-485 device, you can activate the TCF-142旧 termination resistors, and you may need to set up the fiber connection topology. All configuration steps are easy to complete using the 4 DIP switches located on the outside of the TCF-142旧 casing.

TCF-142 media converters can be configured for the following topologies:

1) Pair Connection Mode should be used when you need to connect two remote devices transmitting data over a serial interface, or when you need to increase the “physical” length of the RS-485 line.

An important feature of the TCF-142 is that it does not transmit RS-232 service signals and is not equipped with proper inputs. If the linked serial devices involve hardware data transfer control, you need to close DTR-DSR and RTS-CTS contacts on both devices.

Pair connection mode can be used to combine several RS-485 lines into one serial network as shown in the figure below. The disadvantage of using pair connection is that two TCF-142 units are required for each serial device.

2) Ring Connection Mode provides users with a cost-effective alternative to using pair connection mode. In this case, TCF-142 converters are connected to form a closed fiber-serial ring by connecting the optical transmitter of one TCF-142 to the optical receiver of the neighboring TCF-142. Data packets transmitted by one converter are sent to the adjacent converter, which in turn forwards the packets to the next converter, until the signal reaches the converter that sent the original signal. Ring connection mode is illustrated in the following figure.

Summary
After comparing pair connection mode and ring connection mode, it should be clear that ring connection mode requires fewer converters, and reduces the length of fiber cable required. When using a ring structure, the total length of fiber cable required can be around 100 km. The only drawback to using ring connection mode is that the failure of one fiber cable will cause the entire system to fail.

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