GE S20330-SRS CPU Module

GE S20330-SRS

The GE S20330-SRS  is a VAIC VME Analog Input/Output Board from GE’s Mark VI turbine control system. It is used to acquire analog signals from field devices and generate analog control outputs. The board is designed for demanding turbine-control applications and can operate in both simplex and TMR (Triple Modular Redundant) configurations.

1. Product Overview

The S20330-SRS is a revised version of the IS200VAICH1 family. It incorporates analog signal conditioning, multiplexing, A/D conversion and D/A conversion on the board.

2. Technical Parameters

The commonly documented I/O configuration includes:

• Up to 20 analog inputs
• Up to 4 analog outputs
• 16 analog inputs supporting combinations of ±10 VDC, ±5 VDC and 4–20 mA
• 4 additional analog input channels for 4–20 mA / ±1 mA
• 2 analog outputs configurable for approximately 0–20/0–200 mA
• 2 additional 0–20 mA analog outputs
• 16-bit A/D conversion is reported for the analog input section
• Normal scan time: approximately 10 ms at 100 Hz
• VME form factor / single-slot installation

Note: Some online listings give conflicting channel counts and electrical specifications. For an actual replacement or commissioning job, the GE manual GEH-6421 and the exact terminal-board configuration should take precedence over reseller specifications.

3. Main Features

Analog signal acquisition:
The VAIC receives analog signals from field sensors, transmitters and other turbine instrumentation, conditions those signals and converts them into digital information for the Mark VI controller.

Analog output control:
The board converts digital commands from the control system into analog current outputs for connected field equipment.

Signal conditioning:
Integrated signal-conditioning circuitry helps prepare incoming analog signals for conversion and processing.

Simplex and TMR operation:
In a TMR configuration, three VAIC boards located in separate VME racks can process redundant input information. If one VAIC fails, the failed board can be removed from the output path while the remaining boards continue operation.

Compressor protection functionality:
The VAIC hardware/firmware has been documented as supporting compressor stall detection, with the board capable of initiating a trip signal through the control system when the relevant detection condition occurs.

4. Structural Composition

The board generally consists of:

1. VME interface circuitry
2. Analog multiplexer (MUX)
3. A/D converter
4. D/A converter
5. Analog signal-conditioning circuits
6. Input/output interface circuitry
7. Processor and memory circuitry
8. Front-panel indicators
9. PCB and backplane interface

The board works together with an external Mark VI terminal board such as TBAIH1C, which provides the field wiring interface.

5. Application Fields

The IS200VAICH1DAB is primarily associated with GE Mark VI turbine control systems, including applications involving:

• Gas turbines
• Steam turbines
• Power-generation plants
• Turbine instrumentation
• Industrial process control
• Oil & gas facilities
• Heavy industrial automation

It can be deployed in simplex or TMR architectures, depending on the system design.

6. Important Replacement Considerations

When replacing an S20330-SRS, verify:

• Exact part number: S20330-SRS
• Board revision
• Terminal board compatibility, particularly TBAIH1C
• Simplex vs. TMR system configuration
• Field I/O signal types and ranges
• VME rack compatibility
• Firmware/configuration requirements
• Connector and cable condition

One source specifically notes that the S20330-SRS version is intended for the TBAIH1C terminal-board variant and is not simply interchangeable with earlier TBAI variants.

7. Conclusion

The S20330-SRS is a Mark VI VAIC VME analog I/O board designed for high-reliability turbine control. Its principal functions are analog signal acquisition, signal conditioning, A/D conversion, D/A conversion and analog output control. Its support for simplex and TMR architectures makes it particularly suitable for critical turbine-control environments where redundancy and continuous operation are important.