GE IS200TREAH2ACC Emergency Trip Terminal Board

IS200TREAH2ACC is a redundant logic module for turbine protection systems launched by GE. It belongs to the Speedtronic Mark VIe control system and is specifically designed for high-speed rotating equipment such as gas turbines and steam turbines. It achieves high reliability and safety protection through a three-out-of-two (2oo3) voting mechanism.
Core functions and features
Three-out-of-Two voting logic:
The module performs hardware-level 2oo3 voting on three independent trip/protective signals (such as overspeed, low oil pressure, high vibration).
Only when at least two signals simultaneously trigger a dangerous state will a safety interlock command be output to avoid false tripping or refusal due to a single sensor failure.
Compliant with IEC 61508 SIL2 functional safety standard, ensuring reliable operation even under extreme conditions.
Fast response capability:
Response time ≤ 10ms, meeting the real-time requirements for scenarios such as emergency shutdown of gas turbines.
Flexible input compatibility:
Supports dry contacts (NO/NC) or 24VDC active signal input, compatible with mainstream sensor and relay output levels.
Enhanced isolation design:
Channels and input/output sides adopt ≥1.5kV enhanced isolation to prevent common-mode interference from causing incorrect actions.
High reliability output:
The output is safety relay contacts (Form C, SPDT), rated at 250VAC / 2A, capable of directly driving the trip solenoid valve, shortening the action path.
Intuitive status indication:
Each channel is equipped with an LED indicator (green = normal, red = fault/inconsistent), and the panel provides an “Vote OK” integrated status light.
Comprehensive self-diagnostic function:
Supports fault injection testing and voting logic verification to ensure that the module behaves in accordance with safety specifications under abnormal conditions.

Technical Specifications
Input channels: 3 independent protection signals (Channel A/B/C)
Input voltage range: 0–30VDC
Output type: Safety relay contacts (250VAC / 2A)
Operating temperature: -20°C to +70°C
Protection class: IP54 (dust and water protection)
Certification standards: IEC 61508 SIL2, UL 61010-1, CE EMC Directive

Application scenarios:
Speed protection:
Receive signals from three independent speed probes. Trigger emergency shutdown when any two of them exceed 110% of the rated speed to prevent equipment damage.
Oil pressure monitoring:
Monitor signals from three oil pressure switches. After 2oo3 voting, control the main fuel valve to close to avoid dry friction damage to the bearings.
Electrical fault isolation:
Integrate differential protection, reverse power and other relay outputs to achieve rapid mechanical disconnection in the event of electrical faults.
Unattended operation:
In environments with limited space and difficult maintenance, rely on its high reliability to achieve unattended safe operation.