GE DS200ACNAG1A ARCNET Connect Board

The DS200ACNAG1A is an ARCNET Connect Board designed by General Electric (GE) Industrial Systems for its EX2000 digital exciter system. Belonging to the ACNA (ARCNET Connect Board) series, this board is part of the G1 group and represents revision A. It serves as a core interface component for implementing ARCNET network communication within the EX2000 exciter controller.

The primary function of the DS200ACNAG1A connect board is to provide ARCNET communication connections between the EX2000 main controller, IOS protection modules, and the Mark V SPEEDTRONIC turbine control panel. The board interfaces with the SLCC (LAN Communications Card) via the ARCPL connector, enabling data exchange between the excitation system and the turbine control system. ARCNET is a token-passing local area network protocol known for its high reliability and real-time performance, widely used in industrial control applications.

The DS200ACNAG1A board is designed to meet the demands of industrial excitation systems and features the following characteristics:

• ARCNET Network Interface: Provides dual-channel ARCNET communication interfaces supporting redundant communication configurations.

• Flexible Communication Configuration: Supports configuration as an isolated DLAN circuit or RS-422 driver/receiver mode via hardware jumpers.

• Power Management: Receives +5 V dc power to provide stable operating voltage for the ARCNET communication circuits.

• Simplified Design: The board includes only essential communication interface circuits, with no LEDs, fuses, testpoints, or adjustable switches.

• High Reliability: Utilizes industrial-grade components suitable for harsh industrial environments.

This product is widely used in EX2000 digital exciter systems, power plant excitation control, industrial drive systems, and various industrial control applications requiring ARCNET network communication.

II. Key Functions

1. ARCNET Network Communication Interface

The core function of the DS200ACNAG1A board is to provide an ARCNET network communication interface, enabling data exchange between the EX2000 exciter and external control systems. The board provides two independent ARCNET communication channels (Channel A and Channel B), supporting:

• Dual-Channel Redundant Communication: Enhances system communication reliability.

• High-Speed Data Transmission: ARCNET protocol supports data transmission rates up to 2.5 Mbps.

• Real-Time Communication: Meets the stringent real-time requirements of excitation systems.

2. Interface with SLCC

The DS200ACNAG1A board connects to the SLCC (LAN Communications Card) via the ARCPL connector. The SLCC is the LAN communication board within the exciter controller. The ARCPL connector provides the following signals:

• Channel A Transmit/Receive Signals: TXA-/TXA+, for differential signal transmission on Channel A.

• Channel B Transmit/Receive Signals: TXB-/TXB+, for differential signal transmission on Channel B.

• Auxiliary Communication Signals: TXA, TXB, configurable via hardware jumpers as isolated DLAN circuit or RS-422 mode.

• Power and Common: +5 V dc power and digital common (DCOM).

3. Flexible Communication Configuration

The DS200ACNAG1A board supports communication mode configuration via hardware jumpers. Although the board itself contains no adjustable hardware, its interface with the SLCC allows configuration via jumper JP15 on the SLCC to select:

• Isolated DLAN Circuit Mode: Suitable for applications requiring electrical isolation.

• RS-422 Driver/Receiver Mode: Suitable for long-distance communication or applications requiring an RS-422 interface.

4. Power Management

The DS200ACNAG1A board receives +5 V dc power from the SLCC via the ARCPL connector to power the onboard ARCNET communication circuits. The board has low power consumption and requires no additional cooling measures.

III. Hardware Architecture

1. Board Structure

The DS200ACNAG1A board uses a standard printed circuit board structure with a simplified design, including only essential communication interface circuits. The board includes:

• ARCPL Connector: An 8-pin plug-in connector for interfacing with the SLCC.

• Two BNC Connectors: For connecting ARCNET network cables (Channel A and Channel B).

• Passive Design: The board has no LEDs, fuses, testpoints, or adjustable switches.

2. Mounting Location

The DS200ACNAG1A board is installed within the EX2000 exciter controller module, serving as the physical interface for the ARCNET network, connecting the controller to external networks.

3. Connector Description

4. ARCPL Connector Pin Definitions

IV. Detailed Interface Description

1. ARCPL Connector

The ARCPL connector is the primary interface between the ACNA board and the SLCC (LAN Communications Card), transmitting ARCNET communication signals and power. This 8-pin plug-in connector has the following pin definitions:

2. BNC Connectors

The ACNA board provides two BNC connectors for connecting ARCNET network cables:

• BNC A: ARCNET network physical connection for Channel A.

• BNC B: ARCNET network physical connection for Channel B.

The BNC connectors support the use of RG-62 A/U coaxial cable with a characteristic impedance of 93 ohms. Network topologies can be bus or star configurations, extendable with active repeaters.

V. Configuration and Settings

1. Communication Mode Configuration

The DS200ACNAG1A board itself contains no adjustable hardware. Its communication mode is configured via jumper JP15 on the SLCC to which it connects. The configuration options for JP15 are as follows:

Note: Configuration changes must be made with power off. After changes are made, power must be reapplied for the new configuration to take effect.

2. Network Topology Configuration

The following factors should be considered when configuring the ARCNET network:

• Cable Type: Use RG-62 A/U coaxial cable with a characteristic impedance of 93 ohms.

• Termination Resistors: 93-ohm termination resistors must be installed at both ends of the network.

• Repeaters: When the network distance exceeds 609.6 meters (2000 feet), active repeaters are required.

• Node Addresses: Each node must have a unique network address.

3. Board Replacement Considerations

When replacing an DS200ACNAG1A board, note the following:

• Jumper Settings: The new board’s jumper settings should match those of the old board (the ACNA board itself has no jumpers, but confirm JP15 settings on the SLCC).

• ESD Precautions: Handle boards with a grounding strap and use anti-static packaging.

• Cable Connections: Ensure BNC connectors are secure and cables are undamaged.

VI. Installation and Maintenance

1. Mounting Location

The DS200ACNAG1A board is installed in a slot within the EX2000 exciter controller module, connecting to the SLCC via the ARCPL connector and to the external ARCNET network via BNC connectors.

2. Installation Steps

1. Verify Power is Off: Turn off power to the EX2000 exciter system, wait several minutes for power supply capacitors to discharge, and test to verify that no power exists.

2. Open Cabinet Door: Access the printed wiring board area.

3. Locate the Slot: Identify the installation position for the ACNA board within the controller module.

4. Insert the Board: Align the ACNA board with the slot guides and push it in smoothly until the connectors are fully engaged.

5. Connect Cables:

• Connect the ARCPL ribbon cable to the corresponding connector on the SLCC.

• Connect the ARCNET network cables to BNC A and BNC B connectors.

6. Power On and Verify: After powering on, verify normal ARCNET communication through the control system.

3. Removal Steps

1. Verify Power is Off: Ensure the system has been de-energized and verify that no power is present.

2. Disconnect Cables: Carefully disconnect the BNC connectors and ARCPL cable.

3. Remove the Board: Gently pull out the ACNA board.

4. Maintenance Recommendations

• Periodic Inspection: Regularly check that BNC connectors are secure and cables are undamaged.

• ESD Precautions: Always wear a grounding strap when handling boards. Store boards in anti-static bags.

• Network Status Monitoring: Monitor ARCNET communication status through the control system to promptly identify network issues.

• Spare Parts Management: It is recommended to keep at least one identical ACNA board on-site as a spare to minimize downtime.

VII. Applications

The DS200ACNAG1A ARCNET Connect Board is widely used in the following industrial applications:

• EX2000 Digital Exciter Systems: Serves as the ARCNET communication interface between the exciter and external control systems.

• Power Plant Excitation Control: Connects the exciter to turbine control panels, protection modules, and operator stations.

• Industrial Drive Systems: Provides communication interfaces in industrial drive applications requiring ARCNET network communication.

• Multi-Node Control Systems: Enables high-speed real-time communication in systems with multiple control nodes.

• System Upgrades and Retrofit Projects: Replaces ARCNET interface boards in older systems, enhancing communication reliability.