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        125704-01

        / 4.9
        1001 reviews ｜ Need a Specific Revision?
        The Bently Nevada 125704-01 TMR Relay I/O Module delivers highly reliable relay output conversion with triple modular redundancy, ensuring accurate trip execution through hardware-based 2-out-of-3 voting logic in critical machinery protection systems.
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        Warranty Policy
        We provide 1 year warranty for all remaining parts.
        The warranty period is one year from the date of shipment, unless otherwise stated in the parts description. We guarantee that the project will not exhibit functional defects that may occur under normal operating conditions during the warranty period.
        Return Notice
        The warranty period is one year from the date of shipment, unless otherwise stated in the parts description. We guarantee that the project will not exhibit functional defects that may occur under normal operating conditions during the warranty period.
        In the event of a defect, we will send new equipment, repair equipment or refund the purchase price based on our availability. You must contact us to obtain a return authorization and return the defective device to us within 14 days of reporting the defect.
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        Various transportation options are available in each country. Shipping methods and fees are clearly indicated on all quotations.Various transportation options are available in each country. Shipping methods and fees are clearly indicated on all quotations.
        Parts Availability
        Apter Power offers a wide range of components, products and services related to industrial automation. We also supply new products from a variety of quality manufacturers.
        How to order
        We have been working hard to update our inventory. If we have stock or parts available for new factory purchases, you can contact the order online. If we do not currently have an inventory, the displayed quantity will show "Ask". Please create an online quote or contact us by phone, fax or email to check availability.

        Technical specifications for 125704-01

        • Manufacturer:
          Bently Nevada
        • Part Number:
          125704-01
        • Product Family:
          3500 System
        • Power Consumption:
          9.6 Watts typical.
        • Environmental Sealing:
          Epoxy-sealed.
        • Contact Life:
          100,000 cycles @ 1.5 A, 24 Vdc or 1 A, 120 Vac.
        • Operation:
          Each channel is Normally Energized.
        • Operating Temperature:
          -30 °C to +65 °C (-22 °F to +150 °F)
        • Storage Temperature:
          -40 °C to +85 °C (-40 °F to +185 °F)
        • Humidity:
          95%, non-condensing.
        • Rack Space Requirements:
          1 full-height rear slot.
        • Weight:
          0.52 kg
        • Estimated shipping dimensions:
          2.5x11.2x24.2cm
        • Tariff Code:
          6602000090
        • Country of origin:
          USA
        • Place of shipment:
          Xiamen, Fujian, China
        By purchasing this item, you agree to the Terms & Conditions, ApterPower is not an authorized distributor for listed manufacturers or tradenames and therefore the manufacturer's warranty does not apply. All our products come with ApterPower's 1-year warranty.

        More Information

        Overview Manuals Specifications Communication Application Scenarios Safety

        Features:

        • Triple Modular Redundant Relay Outputs With 2-Out-Of-3 Voting Logic
        • Built-In Alarm Drive Logic Programmable With AND/OR Conditions
        • Supports Integration With Multiple Monitor Channels Via 3500 Rack Software
        The Bently Nevada 125704-01 TMR Relay I/O Module converts processed logic from the 3500/34 TMR Relay Modules into reliable physical relay outputs. It receives three independent Alarm Contact Signals from each relay channel, ensuring accurate execution of critical protection commands.

        The module is designed to operate in conjunction with multiple monitor modules, evaluating each data path independently. If a monitored input indicates a NOT-OK condition, the corresponding Alarm Contact Signal is marked invalid, ensuring that only confirmed alarm conditions drive the outputs.

        Programmed via the 3500 Rack Configuration Software, the Alarm Drive Logic allows operators to combine alerts, dangers, and other channel statuses using AND/OR logic. This flexibility enables customized response strategies for complex machinery protection applications, supporting high-availability operation in demanding industrial environments.

        The 125704-01 Bently Nevada TMR Relay I/O Module may still be available for purchase and support from Apter Power beyond End-Of-Life (EOL) by the manufacturer (OEM).
        Bently Nevada 125704-01 TMR Relay I/O Module Manuals,Datasheets,Link Important Notice: Other accessories, manuals, cables, calibration data, software, etc. are not included with this equipment unless listed in the above stock item description. All prices are shown in USD.
        Bently Nevada 125704-01 TMR Relay I/O Module Specs

        General

        • Manufacturer GE / Bently Nevada
        • Model 125704-01
        • Condition New Original ready stock
        • Product Family 3500/34,125712-02,125712-01
        Important Notice: Other accessories, manuals, cables, calibration data, software, etc. are not included with this equipment unless listed in the above stock item description. All prices are shown in USD.
        • Internal Redundant Bus Connection: This I/O module communicates at high speed with the 3500/34 TMR processor via the 3500 frame backplane, ensuring that instructions from the three independent processing channels reach the physical relays synchronously.
        • Real-time Status Feedback: The module monitors the coil status and contact feedback of each relay in real time and uploads health diagnostic data to the Frame Interface Module (RIM), allowing users to check the communication status in System 1 or configuration software.
        • Write-Protected Communication Lockout: Supports hardware-based communication jumper protection to prevent accidental modification of TMR voting logic or alarm thresholds via remote communication protocols, ensuring the uniqueness and security of instructions.
        • Configuration Synchronization Verification: During system startup or module replacement, the I/O module performs version verification with the main module to ensure complete consistency of the logical configuration on the communication link, preventing false trips due to configuration conflicts.
        • High-Value Unit Protection: Specifically designed for core equipment such as steam turbines and high-power compressors. These devices, if they trip erroneously, can result in millions of dollars in production losses. The TMR module effectively avoids erroneous shutdowns through a "two-out-of-three" logic.
        • Emergency Stop System (ESD) Physical Interface: As the core connection point between the 3500 monitoring system and the plant's overall safety instrumented system, it is responsible for outputting the final physical dry contact signal to cut off the power source.
        • High-Risk Chemical Process Control: Used to execute critical actions such as surge prevention and overspeed protection on production lines with stringent safety requirements, such as ethylene cracking and natural gas liquefaction (LNG).
        • Remote Unmanned Stations: At remote sites such as long-distance pipeline pressurization stations, its extremely high self-diagnostic capabilities and redundancy characteristics reduce on-site manual maintenance caused by false alarms.
        • Two-out-of-three (2-out-of-3) Hardware Voting: This is the core of the module's safety. The final output will only be triggered when at least two of the three processing channels simultaneously issue action commands, greatly improving system availability.
        • SIL 2/3 Functional Safety Compliance: This module is rigorously certified for use in Safety Instrumented Systems (SIS) compliant with SIL 2 or SIL 3 standards, making it one of the highest safety-rated components in the Bently Nevada family.
        • Fail-Safe Design: The relays can be configured for "normal power-on" or "normal power-off" modes. In the event of a complete system power failure, the module automatically enters a preset safe state to prevent protection failure.
        • Comprehensive Self-Diagnostic Functionality: The module continuously monitors backplane communication and tests the relay drive circuitry. If an anomaly is detected in a redundant channel, an alarm will be issued immediately, but the remaining two channels will still maintain normal protection functionality.
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        Description
        The Bently Nevada 125704-01 is designed as the final output interface within the 3500 Machinery Protection System, converting system logic into physical relay (dry contact) outputs. Installed in a full-height rear slot, it works directly with the 3500/34 TMR Relay Module to ensure that protection commands are accurately transmitted to field devices.

        To meet the demands of high-integrity applications, the module adopts a Triple Modular Redundant (TMR) architecture. It utilizes hardware voting logic, where relay actuation only occurs when at least two of the three independent processing channels issue a trip signal. This 2-out-of-3 mechanism significantly reduces the risk of false trips while maintaining dependable shutdown capability in critical situations.

        The module provides six relay output channels operating in a normally energized state, supporting fail-safe behavior. Each relay is epoxy-sealed for enhanced environmental protection and offers a contact life of 100,000 cycles at 1.5 A, 24 Vdc or 1 A, 120 Vac. Compared to standard relay output modules such as 4-channel designs without redundancy, the 125704-01 delivers superior fault tolerance and availability by combining triple redundancy with physical voting circuitry.

        With a typical power consumption of 9.6 Watts, the module is optimized for continuous operation within the rack system. It is engineered for harsh environments, supporting operating temperatures from -30°C to +65°C and storage conditions down to -40°C up to +85°C, along with humidity tolerance of 95% non-condensing.

        In addition, the module supports advanced Alarm Drive Logic through the 3500 Rack Configuration Software, allowing flexible programming using AND/OR logic. Users can integrate alert and danger signals from multiple monitor channels, enabling precise customization of protection strategies for complex industrial applications requiring high availability and system integrity.
        Alternative Names
        125704-02 125704-03 125704-04 133323-01 136188-01 149986-01
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        FAQS

        The following is a list of questions commonly asked by our customers. Please contact us if you have a question about our process that is not answered below.
        VIEW ALL FAQS
        What makes the 125704-01 suitable for safety-critical applications?
        The 125704-01 uses Triple Modular Redundant (TMR) architecture with 2-out-of-3 voting logic, ensuring outputs only actuate when at least two channels agree. This prevents false trips in high-risk machinery protection systems.
        How does this voting logic compare to standard 4-channel relay modules like 125720-02 in terms of reliability?
        Unlike the 4-channel modules, which lack redundancy, the 125704-01 can tolerate a single channel failure without triggering incorrect outputs, providing higher availability and safety in critical operations.
        How does the 125704-01 handle harsh environmental conditions?
        It operates from -30°C to +65°C, stores safely from -40°C to +85°C, and tolerates up to 95% non-condensing humidity. Epoxy-sealed relays improve durability in industrial environments.
        Are there maintenance tips for ensuring reliability under extreme conditions?
        Regular inspection of relay contacts and cleaning the module to prevent dust or moisture buildup can prolong service life. Using the 3500 Rack Configuration Software for periodic logic verification ensures system integrity.

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