GE IS200TRLYH2C Relay Output with Contact Sensing Terminal Board

Technical Dossier

Product Details And Specifications

GE IS200T Series: Comprehensive Module Range and Technical Overview

The GE IS200T series constitutes the primary I/O terminal board family for GE's Mark VI and Mark VIe Turbine Control Systems — the dominant distributed control platform deployed across heavy industrial sectors including petrochemical refineries, nuclear power stations, combined-cycle gas turbine plants, and offshore oil & gas facilities. The IS200TRLYH2C specifically functions as a relay output board with integrated contact sensing, providing hardwired discrete output capability with feedback verification — a critical requirement in safety-instrumented and high-availability turbine control architectures. Installed base for the Mark VI/VIe platform spans tens of thousands of units globally, making IS200T series terminal boards among the most actively sourced industrial spare parts in the power generation and process industries.

The Evolution of IS200T Series Architecture

The IS200T terminal board family was introduced alongside the GE Mark VI control system in the mid-1990s as a modular replacement for the earlier Mark V hardwired I/O architecture. The Mark VI platform standardized on a VME-based backplane with dedicated terminal boards handling signal conditioning, isolation, and field wiring termination — separating the I/O interface layer from the controller logic layer. This architecture allowed field replacement of terminal boards without disturbing controller modules.

With the transition to Mark VIe (introduced circa 2005–2008), GE migrated the control backbone from VME to an Ethernet-based IONet architecture, but retained backward-compatible IS200T terminal board form factors for many I/O types, enabling mixed-generation installations. The IS200TRLYH2C and its variants remained in production through this transition, with hardware revisions (H1, H2, H2C, H2D) reflecting incremental changes to relay specifications, contact sensing circuitry, and conformal coating standards. As of 2026, the Mark VI platform is in its end-of-active-production phase; GE racks and terminal boards are no longer manufactured to order, making certified refurbished and surplus stock the primary sourcing channel for maintenance and emergency replacement.

IS200T Series Full Catalog & Functionalities (SKU List)

Relay Output & Contact Sensing Boards

• IS200TRLYH1A: Relay output terminal board, H1 revision, standard contact configuration
• IS200TRLYH1B: Relay output terminal board, H1B revision, updated relay coil specs
• IS200TRLYH2A: Relay output board with contact sensing, H2A revision, enhanced isolation
• IS200TRLYH2B: Relay output board with contact sensing, H2B revision, conformal coated
• IS200TRLYH2C: Relay output with contact sensing terminal board, H2C revision — primary active spare
• IS200TRLYH2D: Relay output with contact sensing, H2D revision, latest hardware iteration

Analog Input / Output Boards

• IS200TAIAH1A: Analog input terminal board, 16-channel, 4–20 mA / 0–10 V configurable
• IS200TAIAH1B: Analog input terminal board, H1B revision, improved EMI filtering
• IS200TAOAH1A: Analog output terminal board, 8-channel, 4–20 mA output for actuator control

Digital Input / Output Boards

• IS200TDIAH1A: Discrete input terminal board, 24 VDC, 32-channel field wiring interface
• IS200TDOAH1A: Discrete output terminal board, solid-state, 32-channel, 24 VDC sourcing
• IS200TBCIH1C: Bus controller interface terminal board, Mark VI VME backplane interface

Thermocouple / RTD Input Boards

• IS200TTURH1C: Turbine thermocouple input terminal board, 12-channel, J/K/T type
• IS200TTURH2C: Thermocouple input board, H2C revision, extended temperature range support
• IS200TREGH1A: Speed/acceleration input terminal board for turbine speed sensing circuits

Communication & Power Interface Boards

• IS200TSVOH1A: Servo output terminal board, electrohydraulic valve interface, ±10 V / 4–20 mA
• IS200TPROS1A: Protection relay output terminal board, trip-rated, SIL-compatible wiring interface

Sourcing Hard-to-Find & Obsolete IS200T Series Parts

As the Mark VI platform transitions from active production to long-term maintenance mode, procurement of IS200T terminal boards — including the IS200TRLYH2C — increasingly depends on certified surplus and refurbished inventory channels. DriveKNMS maintains a dedicated stock pool of IS200T series boards sourced from decommissioned turbine control panels, OEM overstock, and controlled refurbishment programs. All units are catalogued by hardware revision, functional test status, and cosmetic grade prior to listing. For operators running Mark VI systems under long-term service agreements or managing aging fleet assets, DriveKNMS provides multi-unit lot pricing, cross-revision compatibility assessment, and emergency same-day dispatch for critical spares. Obsolete revision variants (H1A, H1B, H2A) are held in reserve stock specifically for sites where revision-matched replacement is required by site maintenance procedures or OEM service contracts.

Quality Control for the IS200T Series Range

IS200T terminal boards present specific test challenges due to their mixed-signal architecture: relay output circuits, contact sensing feedback loops, and field wiring termination blocks must all be verified independently and in combination. DriveKNMS applies a structured test protocol for the IS200TRLYH2C and related relay output boards: relay coil continuity and pull-in/drop-out voltage verification; contact resistance measurement across NO/NC contacts under rated load; contact sensing circuit loop integrity test simulating field wiring conditions; isolation resistance test between relay coil, contact circuits, and chassis ground (minimum 100 MΩ at 500 VDC); and visual inspection of terminal block condition, PCB trace integrity, and conformal coating coverage. Boards that pass all stages are issued a DriveKNMS test certificate with revision, serial number, and test date recorded. Units with marginal relay contact wear are downgraded to exchange-core status and not listed as ready-to-install spares.