8237-2595 | Woodward ProTech-GII | Safety Overspeed Protection PLC

Overview

The 8237-2595 ProTech-GII from Woodward is a high-integrity overspeed protection controller engineered for mission-critical rotating equipment. Designed as a dedicated Safety PLC, it employs a Triple Modular Redundancy architecture with 2oo3 voting logic to ensure deterministic overspeed detection and fail-safe shutdown execution under all operating conditions.

This system is purpose-built for turbine safety applications where rapid response, diagnostic transparency, and SIL-3 compliance are mandatory. Its robust hardware design and environmental protection enable reliable operation in harsh industrial installations.

System Architecture and Safety Design

The 8237-2595 utilizes three independent processing channels operating in parallel. Each channel continuously evaluates speed inputs and internal diagnostics, with final trip decisions determined through voted logic. This design eliminates single points of failure and allows continued operation even with one channel faulted, while maintaining certified safety integrity.

Integrated self-testing, relay voting, and fault annunciation significantly reduce proof-test effort and lifecycle maintenance risk.

Key Technical Specifications

The 8237-2595 overspeed controller provides the following technical capabilities:

• Safety Integrity Level certified to IEC 61508 SIL-3
• Triple Modular Redundancy with 2-out-of-3 voting logic
• Supported speed sensors: passive MPU or proximity probes
• Three independent speed input channels for redundant measurement
• Configurable overspeed trip logic and diagnostics
• High-speed response suitable for turbine protection loops
• Voted relay outputs for shutdown actuation
• Dual power supply options for AC or DC installations
• Integrated color HMI for configuration and status monitoring
• Native Modbus communication for system integration

Electrical and Performance Data

• Supply Voltage (AC): 90–264 VAC, 47–63 Hz
• Supply Voltage (DC): 18–32 VDC
• Speed Measurement Range: 0.5 to 32,000 RPM
• Typical System Response Time: 8–26 milliseconds (configuration dependent)
• Display: 4.2-inch high-resolution color LCD
• Mounting Method: Bulkhead or panel installation

Environmental and Compliance Characteristics

• Sulfur-resistant conformal coating compliant with IEC 721-3-3 Class 3C2
• Ingress Protection: IP56 when installed in approved enclosure
• Designed for continuous operation in high-vibration industrial environments
• Certified for use in safety-related shutdown systems

Typical Applications

The 8237-2595 ProTech-GII controller is commonly deployed in:

• Gas turbine overspeed shutdown systems
• Steam turbine mechanical protection
• Hydro turbine speed supervision
• Compressors, expanders, and other high-speed rotating machinery
• Safety-instrumented systems requiring certified SIL-3 protection

FAQ

What type of sensors are supported?

The 8237-2595 accepts passive magnetic pickup sensors and proximity probes, allowing compatibility with most turbine speed measurement standards.

Can the system operate with one failed channel?

Yes. The TMR design allows continued safe operation with one channel faulted while maintaining protective coverage.

Is the controller suitable for retrofit projects?

Yes. Its flexible power input, Modbus communication, and bulkhead mounting make it well suited for upgrades and legacy system replacements.