Description
The ABB Bailey IMHSS03 is a specialized slave module designed for the INFI 90 and Network 90 distributed control systems. It functions as a hydraulic servo interface (HSI) and valve position controller, primarily utilized in power generation and heavy industrial applications to manage steam or gas turbine throttle, governor, and bypass valves. The “-MA” suffix typically denotes a specific manufacturing revision or regional distribution identifier designated by Bailey/ABB.
Procurement and Availability
- Availability: Stock dependent; available as new surplus, factory-certified refurbished, or core exchange units.
- Lead Time: 1 to 2 weeks for standard stock items; expedited shipping options available upon request.
- Warranty: 12-month standard warranty on new surplus hardware; 1-year warranty on fully tested repair/refurbished units.
- Pricing Note: Listed price is indicative, not final. Price subject to market conditions; contact us for a firm quote.
Technical Specifications
| Parameter | Value |
| Manufacturer | ABB / Bailey |
| Product Series | INFI 90 / Network 90 / Symphony Harmony |
| Module Type | Hydraulic Servo Slave Module (HSS) |
| Associated Processor | Interfaces with IMMFP01, IMMFP02, or IMMFP03 Multi-Function Processor Modules |
| Feedback Input | LVDT (Linear Variable Differential Transformer) or RVDT position feedback |
| Output Types | Configurable analog control outputs for servo valves or I/H (current-to-hydraulic) converters |
| Auto-Tuning Features | Automatically tunes demodulator gain for optimized valve positioning response |
| Backward Compatibility | Direct replacement for older IMHSS01 and IMHSS02 modules |
| Power Requirements | Powered via module mounting unit (MMU) backplane bus |
| Operating Temperature | 0 to +70 °C |
| Enclosure Rating | Open-type rack-mounted module (IP00; requires installation in a NEMA/IP-rated cabinet) |
System Integration and Compatibility
In field retrofits and turbine control upgrades, the IMHSS03 coordinates directly with multi-function processor (MFP) modules to execute closed-loop positioning algorithms.
- Processor Linkage: The module receives position demand signals from the MFP and drives output stages to minimize positioning error against physical LVDT/RVDT valve feedback.
- Configuration & Jumpers: Board-mounted dipshunts and jumpers must be configured according to the specific actuator type and feedback voltage requirements. Disconnect cabinet power prior to modifying backplane jumpers to avoid electrical shock hazards.
- Replacement Note: When migrating from an IMHSS01 or IMHSS02 to an IMHSS03, verify tuning parameters and demodulator scaling. Consult the specific plant configuration drawings and OEM instruction manuals (such as I-E96-322A) prior to live commissioning.
Frequently Asked Questions
Q: Is the IMHSS03 a drop-in replacement for older IMHSS01 or IMHSS02 cards?
A: Yes, the IMHSS03 is structurally and functionally backward compatible with the IMHSS01 and IMHSS02, providing enhanced internal performance and automatic demodulator gain tuning. Verify termination unit compatibility on the MMU backplane before hot-swapping.
Q: What causes a calibration drift on the LVDT feedback loop?
A: Thermal expansion in high-temperature turbine environments or mechanical wear on linkage arms frequently introduces feedback error. Perform zero and span calibration steps outlined in the hardware manual if positioning hysteresis occurs.
Q: Can this module be repaired if internal component failure occurs?
A: Yes, specialized third-party and OEM repair depots service these legacy boards. Standard repair turnaround times range from 2 to 4 weeks, with rush options often available.
