Product Overview

The Bently Nevada 3701/55 323174-01 ADAPT ESD CPU Module is the processing component of the ADAPT Emergency Shutdown Device used for safety-related protection of rotating machinery and industrial process equipment. It executes configured shutdown logic using speed, discrete and analog input information, then coordinates trip decisions through the system’s relay output architecture.

The ADAPT ESD platform uses a triple-modular-redundant (TMR) architecture with three CPU modules processing shared discrete and analog input information. Each CPU also processes two dedicated speed inputs. This arrangement supports comparison of independent processing results and voting strategies intended to reduce the risk of an incorrect shutdown decision or a missed trip.

The CPU receives its trip logic configuration through Bently Nevada Monitor Configuration software. The application can combine speed limits, process conditions and discrete status signals into shutdown logic with up to 500 logic steps. For maintenance teams, the important considerations are preserving the validated configuration, confirming the input assignments and verifying the complete shutdown path after a module replacement.

Technical Specifications

Product Features

• Triple-redundant processing architecture: Three CPU modules process shared input information to support redundant shutdown decision-making.
• Integrated speed processing: Each CPU processes two speed inputs, supporting overspeed protection applications.
• Discrete and analog input handling: Processes 32 discrete inputs and 12 analog inputs, with analog channels configurable for discrete or 4–20 mA signals.
• Configurable shutdown logic: Supports application logic containing up to 500 logic steps.
• Fast logic execution: Specifies nominal input-to-output logic processing of 2 ms, with an 8 ms relay toggle time.
• Redundant Ethernet connections: Supports network communication through redundant Ethernet interfaces.
• Powered recorder outputs: Provides two internally powered 4–20 mA recorder outputs per CPU.
• Configurable trip behavior: Supports application-specific relay control and voting arrangements, including independent and two-out-of-three voting where configured.
• Software-based configuration: Uses Monitor Configuration software to define shutdown logic and related settings.
• Safety-system integration: Operates as a processing element within a configured ADAPT ESD shutdown system rather than as a standalone replacement for the complete system.

Working Principle

The 323174-01 CPU processes the input information assigned to the ADAPT ESD system. Discrete inputs report equipment states, analog inputs carry supported 4–20 mA signals, and speed inputs provide rotational-speed information for protection functions. The configured logic evaluates these conditions against the application’s shutdown criteria.

The 3701/55 system distributes input processing across three CPUs. Each CPU processes the shared discrete and analog input array and its two unique speed inputs. The resulting decisions are used by the configured relay architecture, which can operate in independent or voting arrangements according to the application.

The CPU executes the logic configured through Monitor Configuration software. Logic can combine multiple conditions, interlocks and voting requirements before a trip command is issued. The nominal logic processing time is 2 ms, while the specified relay toggle time is 8 ms; actual shutdown performance depends on the complete system configuration and the connected trip devices.

The CPU also supports redundant Ethernet communication and provides two internally powered 4–20 mA recorder outputs. These interfaces support system communication and the recording of configured measurements. They do not replace the hardwired safety path or the physical relay output components required to execute a shutdown.

When replacing a CPU, technicians should restore the validated configuration, verify network assignments and confirm the correct input mapping. A successful power-up alone does not demonstrate that the safety function is correct. The complete configured shutdown path must be functionally tested before the protected machinery returns to service.

Role in a Bently Nevada ADAPT ESD Safety Architecture

The 323174-01 is the processing element that evaluates configured protection logic within the 3701/55 ADAPT ESD system. It works alongside the terminal base, input wiring and relay output modules to convert detected process or machinery conditions into defined shutdown actions.

Industrial Applications

Installation and Maintenance

1. Verify the CPU part number: Confirm that the replacement is 323174-01 and belongs to the 3701/55 ADAPT ESD system.
2. Check the system architecture: Verify the installed CPU count and the intended TMR arrangement before removing or replacing a processing module.
3. Follow approved isolation procedures: Apply the site’s safety and maintenance procedures before working on the shutdown system or its power connections.
4. Inspect the terminal base: Check the 289761-01 terminal base and its connectors for damage, contamination or loose connections.
5. Confirm input assignments: Verify the discrete, analog and speed input mapping against the approved application drawings.
6. Check the power supply: Confirm that the system supply remains within the specified 18–36 V DC input range and meets the system’s power requirements.
7. Verify network connections: Inspect both Ethernet connections, confirm the configured network settings and check for communication faults.
8. Restore the validated configuration: Load or verify the approved Monitor Configuration settings and confirm that the correct logic version is in use.
9. Inspect relay output modules: Confirm that the installed 323073 series relay modules and their relay options match the application design.
10. Test input processing: Verify the expected response to simulated or approved test signals for discrete, analog and speed inputs.
11. Perform a complete trip test: Validate the configured logic, voting behavior, relay actuation and external shutdown response using the approved proof-test procedure.
12. Record commissioning results: Document the CPU reference, configuration version, network settings, test results and any outstanding faults before returning the system to service.

Compatible System Components

Recommended Related Models

Key Advantages

• Executes configured shutdown logic within the 3701/55 ADAPT ESD system.
• Supports a triple-modular-redundant processing architecture.
• Processes discrete, analog and speed-related protection inputs.
• Supports configurable trip logic with up to 500 logic steps.
• Provides redundant Ethernet connections and powered 4–20 mA recorder outputs.
• Supports integration with the system’s relay output modules and external trip circuits.

Technical FAQs

What is the role of the 323174-01 CPU in a triple-modular-redundant ADAPT ESD system?

Each CPU independently processes the applicable input information and evaluates the configured trip logic. The three-CPU architecture supports redundant decision-making and configured voting strategies; the CPU is one part of the complete shutdown system, not a standalone ESD solution.

How are the 12 analog inputs used in the ADAPT ESD application?

The system processes 12 analog inputs that can be configured for discrete or 4–20 mA analog signals. The actual use of each channel depends on the approved application configuration, transmitter type and assigned shutdown logic.

What is the difference between the 2 ms logic processing time and the 8 ms relay toggle time?

The 2 ms figure describes nominal processing time for the input-to-output decision logic. The 8 ms figure describes relay toggle time. The complete time to achieve a physical shutdown also depends on the configured system, relay circuit and external trip device.

Why must the full shutdown function be tested after replacing a CPU module?

A CPU can start successfully while input mapping, network configuration, logic settings or relay behavior remain incorrect. A complete functional test verifies that the configured conditions produce the intended trip response and that the external shutdown path operates as required.