DS200MBHAG1AFC | GE Surplus Stock

Description

Product Introduction

The DS200MBHAG1AFC is the fiber optic variant of GE’s Modbus gateway for the Mark V. Standard copper Modbus dies in electrically noisy substations—ground loops, VFD hash, and lightning-induced surges eat transceivers for breakfast. This board replaces copper with glass.

The “FC” suffix means Fiber Converter. Same processor (Infineon C167CR at 40MHz) and same 1MB RAM as the standard G1A, but the RS-232/RS-485 drivers are gone. Instead, you get two ST-type fiber ports running at 850nm. The practical advantage? You can run Modbus 2,000 meters from the turbine control room to the plant SCADA without worrying about ground potential differences. We’ve seen copper Modbus networks fail weekly at hydroelectric plants where grounding mats float by 50 volts. The fiber version runs for years.

Key Technical Specifications

Compatible Replacement Models

✅ Drop-in Replacement: DS200MBHAG1A
Standard RS-232/RS-485 version. Same processor, same RAM, same firmware. Swaps directly only if you also change your serial cabling from fiber to copper. The backplane doesn’t care. Your field wiring must match the board’s physical layer.

✅ Drop-in Replacement: DS200MBHAG1
Older processor version (80C166 at 25MHz) with copper serial ports. Swaps directly but expect slower scan times. The FC version is about 60% faster under heavy polling loads. Not recommended if you poll more than 100 registers per second.

⚠️ Software Compatible: DS200MBHAG1A (any copper variant)
Same firmware image works across copper and fiber versions. The physical layer is transparent to the protocol stack. You can take a configuration backup from a copper board and restore it to an FC board with no changes.

❌ Hardware Incompatible: DS200MBHAG1A with third-party fiber converters
You can add external copper-to-fiber converters to a standard MBHAG1A, but that adds two conversion points and about 0.5dB loss per converter. The native FC board eliminates those failure points. Do not attempt to retrofit fiber transceivers to a copper board—the PCB lacks the mounting holes and the power supply filtering.

Frequently Asked Questions (FAQ)

Can I mix fiber and copper Modbus gateways on the same VME backplane?
Yes. The backplane doesn’t care. You can have an FC board in slot 4 talking to a remote SCADA via fiber, and a standard G1A in slot 6 talking to a local HMI via RS-485. Both boards operate independently. The only restriction: each board’s two ports must use the same physical layer. You cannot have Port 1 on fiber and Port 2 on copper on the same FC board.

How do I visually identify a genuine FC board vs a standard G1A with external converters?
Three tells:

1. Fiber ports: Genuine FC boards have ST barrels mounted directly to the PCB edge. Standard boards have a blank panel or DB9 connectors in that location.
2. Missing U8: On a standard G1A, U8 is a MAX485 transceiver (8-pin DIP). On an FC board, that location is empty with a jumper shunt installed.
3. Power regulator heatsink: FC boards have an additional heatsink on U5 (the 3.3V regulator for the fiber transceivers). Standard boards run cooler and use a smaller heatsink.

What’s the typical failure mode on the FC board?
The fiber transceivers (same Avago HFBR-1414T/HFBR-2416T as the LAN board) eventually lose optical power. However, the Modbus gateway’s transceivers run continuously, unlike the LAN board which only transmits when polled. In a typical SCADA setup polling every second, the FC board’s transmitters see about 31 million on-off cycles per year. After five years, output drops by about 1.5dB. Symptoms: intermittent timeouts, CRC errors, or the TX LED flashing without a corresponding RX LED on the receiving device. Replace the transceivers—they’re press-fit, 15 minutes each.

Can I use this board as a Modbus-to-fiber converter for non-GE devices?
Technically yes, but overkill. The board still needs to sit on a Mark V backplane for power and configuration. You’d need a powered Mark V rack just to run this board as a standalone converter. That’s 500 worth of backplane and power supply for a 200 converter function. Buy a standalone industrial fiber-to-serial converter (e.g., B&B Electronics FOSTCDR) for $350 instead.

My fiber link works at 9600 baud but fails at 115200. What’s wrong?
You have excessive dispersion or attenuation. At 115200 baud, the bit time is 8.68µs. The fiber transceivers have a rise time of about 3ns—not the issue. The problem is almost always connector losses. Each dirty or misaligned ST connector adds 1-3dB loss. At 9600 baud, the receiver can tolerate -28dBm. At 115200, the threshold is -24dBm. That 4dB difference means two marginal connectors will kill high-speed but work at low speed. Clean every connector. If that doesn’t fix it, measure optical power at the receiver—should be above -20dBm.

How do I test a used DS200MBHAG1AFC without a Mark V rack?
You can’t easily. The board requires 5V and 3.3V power from the backplane. However, you can build a bench test fixture:

1. Wire a standard ATX power supply’s 5V rail to pins 4C and 4D on the backplane edge.
2. Ground to pins 1A, 1B, 1C.
3. Apply power. The PWR LED should illuminate solid.
4. Connect fiber to a known-good device (e.g., a fiber-to-serial converter connected to a laptop running ModScan).
5. Poll the board at its default address (1) and baud rate (9600).
   If you get no response, the board is likely dead. Without the full backplane handshake, you can’t write configuration or change settings. This test only confirms basic transceiver function.

What’s the lead time for a replacement DS200MBHAG1AFC from surplus stock?
Typically 5-10 business days. These are rare—about 5% of Modbus gateways shipped were FC variants. Most plants use external copper-to-fiber converters instead of the native board. If you need one urgently, we can pull from our “deep storage” inventory for a 30% premium. Expect 2-day expedited shipping.

Do you offer any warranty for FC boards used in outdoor cabinets?
Standard one-year replacement warranty. However, the fiber transceivers are not sealed against humidity. We’ve seen condensation inside ST barrels at sites with poor climate control. The moisture attenuates the signal and eventually corrodes the transceiver lens. If your cabinet sees dew point, install sealed bulkhead adapters with gaskets. Also consider the EC (Extended Conformal) version if available—though GE never officially released an FC with EC coating. To be frank, the FC board is not suited for outdoor use without additional environmental protection.

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