Description
- Model: GE WESDAC D20 A
- Brand: GE / GE Harris
- Series: WESDAC D20 RTU (Remote Terminal Unit)
- Core Function: High-speed data acquisition and control processing for electrical substations
- Product Type: Main Processor / Control Module
- Key Specs: VME-based architecture, multi-protocol support (DNP3, Modbus), high-density I/O handling
GE WESDAC D20 A
Key Technical Specifications
- Processor Architecture: 32-bit RISC processing core
- Operating System: pSOS or equivalent real-time operating system (RTOS)
- Communication Ports: RS-232, RS-485, and 10Base-T Ethernet options
- Protocol Support: DNP 3.0, Modbus RTU/TCP, Harris 5000/6000, and IEC 60870-5-101/104
- Backplane Interface: Standard VMEbus
- Memory: Integrated Flash for firmware and SRAM/DRAM for real-time data buffering
- I/O Capacity: Supports hundreds of digital and analog points via peripheral D20 modules
- Diagnostics: Integrated watchdog timer and system health LEDs
- Power Requirement: Typically supplied via D20 PSU (+5 V, ±12 V DC)
- Environmental Rating: Designed for high-EMC substation environments (-20 °C to +70 °C)
GE WESDAC D20 A
Installation & Configuration Guide
Phase 1: Pre-Installation (Estimated time: 15 minutes) ⚠️ Safety First:
- Ensure the substation “Control DC” power is isolated or the D20 rack is powered down.
- Firmware Check: The D20 A module uses EPROMs or Flash for firmware. Ensure the version on your spare matches the current system configuration to avoid database mismatches.
- Use a grounded anti-static wrist strap. The VME backplane is sensitive to static discharge.
Phase 2: Removal (Estimated time: 10 minutes)
- Label Serial Cables: The D20 A often has multiple RS-232/485 connections for SCADA and local I/O. Label these clearly (e.g., COM1, COM2).
- Eject the Module: Use the upper and lower ejector handles. Pull them outward simultaneously to unseat the 96-pin connectors.
- Inspect Pins: Check the VME backplane for any bent pins or signs of “arcing” if the previous module failed due to a surge.
Phase 3: Installation (Estimated time: 20 minutes)
- Duplicate Settings: Match the DIP switches and jumpers (addressing and baud rates) from the old D20 A to the new unit.
- Slide and Seat: Align the module in the VME rack guides. Push firmly until the module handles can be flipped inward to lock the board.
- Reconnect Communications: Plug in your serial and Ethernet cables. Ensure the DB9 or DB25 connectors are screwed in tight to prevent vibration-related signal loss.
Phase 4: Power-On & Testing (Estimated time: 30 minutes)
- Apply power to the RTU rack.
- Status LEDs: Watch the “Run” and “Error” LEDs. A successful boot shows a steady green Run light.
- D20 Config Tool: Connect a laptop to the “Maintenance” port. Use the GE Configurator software to upload the existing configuration file (.bin or .dat).
- Point Mapping: Verify that the D20 A is successfully polling its peripheral I/O modules (D20 S, D20 K, etc.) and that data is reaching the Master Station (SCADA).
GE WESDAC D20 A
Customer Cases & Industry Applications
Case 1: Rural Utility Substation Recovery A rural electric cooperative in the Midwest experienced a lightning strike that damaged the main processor in their D20 RTU. Without the WESDAC D20 A, the utility lost all remote visibility and control of their breakers, requiring technicians to drive 2 hours for every manual switching operation. We delivered a New Surplus D20 A in 48 hours. By swapping the module and reloading the config file, they restored SCADA communication in less than 20 minutes of on-site work.
Case 2: Industrial Power Management Stability A large aluminum smelter used the D20 A to manage its high-voltage switchgear. The original processor began experiencing “memory leaks,” leading to random reboots. Knowing the D20 series is an older but reliable platform, they purchased two New Surplus units as part of a strategic buffer stock. During the next scheduled outage, they replaced the aging processor, eliminating the reboots and extending the life of their existing automation infrastructure by another decade.
Frequently Asked Questions (FAQ)
Q: Is the WESDAC D20 A compatible with the newer D20 MX or D200 models? A: To be honest, they are different generations. While the D20 A can often communicate with D200 systems via the D20 Link, it is a VME-based board specifically for the classic D20 RTU rack. You cannot physically plug a D20 A into a D200 chassis.
Q: Do I need to move the EPROMs from my old board to the new one? A: In my experience, if the new board has the same or newer firmware, you can simply download your configuration file. However, if your system uses highly customized legacy protocols, moving the EPROMs (carefully!) is sometimes the fastest way to ensure 100% compatibility.
Q: Why is my “Error” LED blinking after I installed the new module? A: This usually means the board is healthy but “unconfigured.” It’s waiting for the configuration file to be uploaded via the maintenance port. If it remains red after an upload, check for a VME address conflict with other boards in the rack.
Q: Does “New Surplus” mean it’s been sitting in a warehouse for 10 years? A: It might have been, but that’s actually a good thing for these legacy parts. These are original components kept in climate-controlled storage. They haven’t been subjected to the heat and electrical stress of a substation environment, meaning their internal components (like capacitors) are in far better shape than a “refurbished” or used unit.
Q: Can you help me find the right configuration software? A: We provide the technical manuals and pinout guides. While we don’t officially distribute GE proprietary software, we can point you toward the correct version (e.g., Config61850 or D20 Config) you’ll need to talk to this specific hardware.
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