Product Overview
The BENTLY 3500/34 is a high-integrity triple modular redundancy (TMR) relay module, serving as a cornerstone of safety in Bently Nevada’s 3500 Machinery Protection System. Designed for mission-critical applications where failure tolerance is non-negotiable, this module translates critical machinery data into reliable alarm and shutdown signals, ensuring uninterrupted protection even in the event of internal component faults.
As part of the 3500 series, the BENTLY 3500/34 builds on the system’s reputation for robustness by incorporating TMR architecture—three independent relay channels operating in parallel, with voting logic to eliminate single-point failures. This design makes it ideal for industries where equipment failure could lead to catastrophic consequences, such as nuclear power or offshore oil production. The BENTLY 3500/34 seamlessly integrates with 3500 monitor modules (like the 3500/42M), processing their outputs to trigger safety actions only when consensus is reached across all three channels, minimizing false alarms. Its ability to deliver both high reliability and rapid response solidifies its role as a trusted safety interface in the most demanding industrial environments.
Technical Specifications
| Parameter |
Value |
| Product Model |
BENTLY 3500/34 |
| Manufacturer |
Bently Nevada |
| Product Type |
TMR (Triple Modular Redundancy) Relay Module (3500 Series) |
| Number of Relay Channels |
3 independent TMR channels (each with redundant relays) |
| Relay Type |
Double Pole Double Throw (DPDT) per channel |
| Maximum Switching Voltage |
250 VAC / 125 VDC |
| Maximum Switching Current |
5 A (resistive load) |
| Response Time |
<15 ms (from input signal to relay actuation) |
| Redundancy Architecture |
Triple parallel channels with majority voting logic |
| Input Interface |
3500 backplane (receives signals from monitor modules) |
| Operating Voltage |
+5 VDC (from 3500 rack backplane) |
| Operating Temperature |
0°C to +60°C |
| Mounting |
3500 Series Rack (2-slot width) |
| Compliance |
IEC 61508 (SIL 3), ATEX, IECEx, UL 508 |
Key Features and Benefits
The BENTLY 3500/34’s TMR architecture is its defining strength, with three identical channels processing signals simultaneously. Majority voting ensures that a single channel fault does not affect output—only when two or more channels agree on an abnormal condition does the relay actuate. This eliminates false shutdowns, a critical advantage in industries where unplanned downtime is costly or dangerous.
Rapid response time, under 15 ms, ensures the BENTLY 3500/34 acts quickly to mitigate risks, such as triggering emergency shutdowns when excessive turbine vibration is detected. Its DPDT relays offer flexible wiring options, allowing integration with diverse safety systems—from audible alarms to emergency stop valves—without needing additional interface modules.
The module’s diagnostic capabilities provide real-time status of each TMR channel via the 3500 system interface, enabling maintenance teams to identify and address faults in individual channels without disrupting overall operation. Compliance with SIL 3 standards underscores its suitability for safety-critical applications, while its rugged design withstands vibration, temperature fluctuations, and electromagnetic interference common in heavy industrial settings.
Seamless integration with the 3500 ecosystem simplifies configuration via the 3500 Rack Software, allowing users to tailor voting logic and response thresholds to specific machinery requirements, enhancing adaptability across industries.
Application Scenarios
The BENTLY 3500/34 is indispensable in industries where safety and reliability are paramount. In nuclear power plants, it protects reactor coolant pumps by processing vibration and temperature data from 3500/42M modules, triggering shutdowns only when all three TMR channels confirm critical conditions—preventing unnecessary reactor trips that could cost millions.
Offshore oil platforms rely on the BENTLY 3500/34 to safeguard subsea compressors, where a single fault could lead to oil spills or explosions. Its ATEX certification ensures safe operation in hazardous zones, while TMR logic guarantees that sensor or wiring errors do not compromise safety actions.
In chemical processing facilities handling toxic or flammable materials, the BENTLY 3500/34 manages safety interlocks for agitators and reaction vessels. By requiring consensus across all three channels, it avoids false shutdowns that could disrupt batch processes or release harmful substances.
Even in aerospace ground support, where turbine test cells operate at extreme power levels, the BENTLY 3500/34 provides the reliability needed to protect personnel and equipment from catastrophic failures during high-stakes testing.
Related Models
3500/32 125712-01 – 4-channel non-TMR relay module, a cost-effective alternative to BENTLY 3500/34 for less critical applications.
3500/33 125713-01 – 8-channel standard relay module, compatible with BENTLY 3500/34 in mixed-safety-level systems.
3500/42M 125808-01 – Vibration monitor module that supplies input signals to BENTLY 3500/34 for TMR processing.
3500/34-01 – Enhanced variant of BENTLY 3500/34 with extended temperature range (-20°C to +70°C) for extreme environments.
3500/15 125771-01 – Communication module that transmits BENTLY 3500/34 status data to SCADA systems for remote monitoring.
3500/92 125782-01 – System display module that visualizes TMR channel status from BENTLY 3500/34.
3500/22M 138607-01 – Redundancy monitor that works with BENTLY 3500/34 to ensure power supply integrity in TMR setups.
Installation and Maintenance
Installation of BENTLY 3500/34 requires a 2-slot space in the 3500 rack, with secure insertion into the backplane to ensure reliable communication and power. Wiring to external safety systems must use shielded cables to minimize interference, with each relay output connected to its respective safety device (e.g., shutdown solenoids). Prior to operation, configure voting logic and thresholds via 3500 software, ensuring alignment with site safety protocols. Grounding the rack per local codes is critical to prevent electrical noise from affecting TMR channel consensus.
For maintenance, inspect BENTLY 3500/34 quarterly by checking front-panel LEDs—steady green indicates all channels are operational, while amber signals a single-channel fault. Test TMR functionality semi-annually by simulating faults in one channel and verifying the module continues operating correctly. Download fault logs monthly to track channel performance trends. Replace the module every 10-12 years under normal operation, or immediately if two or more channels fault simultaneously, to maintain SIL 3 integrity.
Product Warranty
The BENTLY 3500/34 is backed by a one-year warranty from Xiamen Xiongba E-commerce Co., Ltd., covering manufacturing defects and performance issues under normal operating conditions. During this period, we provide free replacement for any unit that fails to meet TMR response time, voting logic, or safety compliance standards, ensuring your 3500 Machinery Protection System remains reliable in critical applications. Our technical support team offers expertise in TMR configuration, integration with monitor modules, and troubleshooting, leveraging over a decade of industrial automation experience. We stand behind the BENTLY 3500/34’s role in safety-critical environments, ensuring customers receive consistent performance and responsive service to protect their operations and personnel.
Company Introduction: We offer a one-year warranty and free replacement service:
Xiamen Xiongba E-commerce Co., Ltd. Branch specializes in the field of industrial automation, focusing on the sales of Distributed Control Systems (DCS), robot systems, and modules and spare parts for large-scale servo control systems. Our business covers a wide range of industrial automation products, including PLCs, MOTOROLA MVME industrial modules, Anybus communication converters, RTU remote modules, industrial PCs, low-frequency industrial displays, and SCSI human-machine interfaces. With over a decade of industry experience, Xiongba has grown into a global supplier of industrial automation spare parts. We source directly from overseas, offering products and parts from multiple countries and manufacturers. This helps solve customers' procurement challenges, ensures product quality, and provides a significant price advantage.
