GE IS200TSVOH1B Termination Board Servo – IS200T Series Modules

Technical Dossier

Product Details And Specifications

GE IS200T Series Technical Notes

The GE IS200T series represents a core family of I/O termination and interface boards deployed within GE's Mark VI, Mark VIe, EX2100, and LCI turbine and excitation control platforms. These modules are installed across heavy industrial sectors including petrochemical refineries, nuclear power stations, combined-cycle gas turbine plants, and offshore oil & gas facilities. The IS200T series functions as the physical interface layer between field instrumentation and the Mark VI controller backbone, handling servo control, analog I/O, digital I/O, thermocouple inputs, and power distribution. Their ruggedized PCB construction and deterministic signal routing make them a long-term fixture in plant control architectures where replacement cycles span 15–25 years.

The Evolution of IS200T Architecture

The IS200T series was introduced alongside the Mark VI control system in the mid-1990s as GE transitioned from the earlier Mark V platform. Early IS200T boards used passive backplane termination with discrete wiring to field devices. As the platform matured through the Mark VIe generation (introduced circa 2005), GE introduced enhanced IS200T variants with improved EMI shielding, higher-density connector blocks, and compatibility with the IONET and ARCNET communication buses used in distributed I/O configurations.

Compatibility between early Mark VI IS200T boards and Mark VIe controllers requires careful firmware and hardware revision matching. Boards manufactured before 2003 (identifiable by revision suffix A–C) may require adapter harnesses when retrofitted into newer cabinets. The IS200TSVOH1B specifically serves the servo output termination function, providing the physical connection point for electrohydraulic servo valve (EHSV) control signals in turbine governor and fuel control loops. As of 2026, the IS200T series is in its mature/end-of-life phase; GE no longer manufactures most variants, making aftermarket sourcing and lifecycle extension services critical for plant operators.

IS200T Full Catalog & Functionalities (SKU List)

Servo & Actuator Control Termination Boards

• IS200TSVOH1B: Servo output termination board for EHSV control in Mark VI turbine governor loops
• IS200TSVCH1B: Servo valve control termination board, high-current variant for large-frame turbines
• IS200TSVOH1A: Earlier revision of servo output termination board; compatible with Mark VI Rev A cabinets
• IS200TRLYH1B: Relay output termination board; 16-channel discrete relay interface for trip and alarm circuits
• IS200TTURH1C: Turbine trip relay termination board; hardwired safety interlock interface

Analog I/O Termination Boards

• IS200TAIAH1B: Analog input termination board; 16-channel 4–20 mA field input interface
• IS200TAICH1B: Analog input termination board with cold junction compensation for thermocouple inputs
• IS200TAOAH1B: Analog output termination board; 8-channel 4–20 mA output for valve positioners
• IS200TRTDH1C: RTD input termination board; supports PT100/PT1000 3-wire and 4-wire configurations
• IS200TTCIH1B: Thermocouple input termination board; Type J, K, T, E, R, S, B thermocouple support

Digital I/O Termination Boards

• IS200TDIAH1B: Digital input termination board; 32-channel 24 VDC discrete input interface
• IS200TDOAH1B: Digital output termination board; 16-channel 24 VDC sourcing output
• IS200TDIOH1B: Combined digital I/O termination board; 16 DI + 8 DO mixed configuration

Power Supply & Communication Interface Boards

• IS200TPSH1B: Power supply termination board; distributes 28 VDC and 5 VDC rails to I/O modules
• IS200TCNBH1B: Communication network termination board; IONET/ARCNET bus interface for distributed I/O expansion
• IS200TPROH1B: Processor interface termination board; direct backplane connection to VCMI or VCRC controller cards

Sourcing Hard-to-Find & Obsolete IS200T Parts

DriveKNMS maintains a dedicated inventory of IS200T series boards sourced from decommissioned Mark VI cabinets, controlled plant shutdowns, and OEM surplus channels. For end-of-life variants such as the IS200TSVOH1A, IS200TAIAH1A, and IS200TDIAH1A (all discontinued prior to 2010), DriveKNMS provides:

• Board-level inspection and functional verification prior to shipment
• Revision-matched sourcing to ensure compatibility with existing cabinet configurations
• Long-term supply agreements for plants requiring multi-year spare parts coverage
• Cross-reference support to identify compatible substitute boards where direct replacements are unavailable

Plants operating Mark VI systems beyond their original design life (typically 20+ years) face increasing difficulty sourcing IS200T boards through standard OEM channels. DriveKNMS specializes in bridging this gap with verified aftermarket inventory and technical documentation support.

Quality Control for the IS200T Range

IS200T series boards present specific test challenges due to their multi-layer PCB construction, high-density connector arrays, and mixed analog/digital signal paths. DriveKNMS applies the following test protocol to all IS200T boards prior to dispatch: