Description
Product Overview
The GE DS200SIOBH1ABA is a serial and discrete input/output board from the DS200 line of the GE Speedtronic Mark V turbine control system. Within the rack it carries the SIOB designator, and it occupies one 6U slot on the VME backplane.
No processor sits on this card. It operates as a VME slave, handling buffering, isolation and level conversion, while the main Mark V controller keeps every control decision. That split keeps scan behaviour predictable and lets the board be replaced without touching control logic.
The ABA revision is the mixed-port version of the family. Where the AAA board provides three RS-485 channels, this one carries two serial ports that a technician can configure as RS-232 or RS-485 through jumpers. A rack wired for one revision will not simply accept the other.
It also brings sixteen discrete inputs and sixteen discrete outputs along for the ride, which is why plants often use it as a single answer to both serial and interlock needs.
GE DS200SIOBH1ABA
Product Features
Two mixed serial ports suit racks where short-haul terminal links and long RS-485 runs coexist, so one card covers both without a second slot.
- Each serial channel runs 300 bps to 115.2 kbps, with automatic baud detection to cut commissioning time on replacements.
- Modbus RTU, ASCII, DF1 and GE proprietary serial formats all pass through the same hardware, so third-party meters and GE terminals coexist on one rack.
- Sixteen 24 VDC opto-isolated inputs and sixteen 24 VDC transistor outputs handle interlock feedback and relay driving at 0.5 A per channel.
- A 1500 Vrms barrier separates serial ports, discrete I/O and the VME backplane, keeping ground loops out of the control electronics.
- Surge and ESD protection circuits guard every field entry ahead of the logic stage, which matters during storm season and maintenance outages.
- Twenty jumpers across three switch blocks define port mode, bus address, parity and termination, so setup stays local and repeatable.
- Half-duplex VME traffic at 5 Mbps keeps I/O refresh tight enough for governing duties.
- Conformal coating, gold-plated terminals and a single front-panel LED complete the package for humid plant rooms and quick walk-by checks.
Technical Specifications
| Item | Specification |
|---|---|
| Ordering model | DS200SIOBH1ABA |
| Series designator | SIOB, H1 group, ABA revision |
| Manufacturer | General Electric |
| Product type | Serial and discrete I/O board |
| System platform | GE Speedtronic Mark V turbine control |
| Bus role | VME slave, 6U Eurocard |
| Serial ports | 2, jumper selectable RS-232 / RS-485 |
| Baud rate | 300 bps to 115.2 kbps, auto-baud detection |
| Protocols | Modbus RTU, ASCII, DF1, GE proprietary serial |
| Isolation rating | 1500 Vrms, ports and I/O to VME backplane |
| Digital inputs | 16 channels, 24 VDC, opto-isolated |
| Digital outputs | 16 channels, 24 VDC, 0.5 A per channel |
| VME bus speed | 5 Mbps, half duplex |
| Power source | +5 VDC from the VME backplane |
| Power draw | 2.5 A typical, 3 A maximum |
| Configuration | 20 jumpers, 3 switch blocks, 1 status LED |
| Operating temperature | -40°C to +70°C, non-condensing |
| Humidity | 5% to 95%, non-condensing |
| Protection rating | IP20 |
| Coating | Conformal coating applied |
| Bus termination | 120 Ω at the two physical ends |
Port count is the one figure where catalogues disagree, with some listings claiming four channels and a 2500 VAC isolation level. Treat the two-port mixed layout and the 1500 Vrms barrier as the working baseline, then confirm against the board label and the rack wiring diagram in front of you.
Product Details
A walk through the signal path explains most field behaviour better than a spec sheet does.
Power entry. The backplane delivers +5 VDC, and onboard regulators clamp transients while flagging overload. Repeated rack resets usually trace back here rather than to the serial device.
Protection order. Field lines pass through surge and ESD protection first, then through the isolation barrier, and only then into the UART or the discrete logic. A fault in the first stage reads like a dead port in the last stage, so test in sequence.
Serial stage. UART chips handle framing, and auto-baud locks onto an incoming rate when the attached device cooperates. Devices with unusual framing still need manual switch settings.
Discrete stage. Inputs run through opto-couplers, outputs through transistor drivers. Anything with a high inrush, such as a large solenoid, belongs on a separate relay board instead of these channels.
Termination. RS-485 segments want a 120 Ω resistor at the two physical ends only. Terminating every node creates the reflections technicians were trying to eliminate.
Configuration. A plant’s wiring plan lives in the jumper layout rather than in memory. Photograph the old board, then compare switch by switch after installation.
Revision awareness. ABA means two mixed ports. Fitting one into a rack planned for an AAA leaves the third channel silent even though the LED looks healthy. Match the part number to the port plan before the swap.
Board size follows the standard Mark V 6U footprint at roughly 2.1 cm × 18.8 cm × 26.2 cm, around 0.36 kg. These figures come from GE-line field documentation and distributor data, so verify them against the unit label at acceptance.
GE DS200SIOBH1ABA
Application Fields
The mixed-port design explains where this board earns its keep.
Combined-cycle turbine racks. An operator panel on a short RS-232 cable and a remote Modbus device on a long RS-485 run both fit on the same card, which simplifies panel layout.
Refinery and compressor packages. Skids with Modbus RTU instruments need the long-haul channel, while local diagnostic terminals want the short one.
Balance-of-plant integration. Water treatment skids, auxiliary boilers and cooling systems usually speak Modbus RTU only, and one serial channel brings them into the turbine control narrative without a gateway.
Legacy fleet support. Plants maintaining Mark V racks stock ABA boards as spares because a card swap costs far less than a platform migration.
Service benches. Repair shops reproduce plant serial behaviour on a bench before travelling to site, shortening outage windows noticeably.
Related Model Recommendations
- DS200SIOBH1AAA — three RS-485 ports instead of two mixed channels. Choose it when every remote drop speaks RS-485 and no RS-232 terminal is involved.
- DS200SIOBH1ACA — later A-series revision with two 25-pin serial connectors. Same slot, different port plan, so check the wiring before substituting.
- DS215DMCBG1AZZ03A — Mark V processor and communication board, the natural partner when a rack needs both the control side and the serial side refreshed.
- DS200TCRAG1ACC — relay output board for loads above the 0.5 A channel rating, paired with SIOB where interlock circuits switch heavier currents.
