Bently 3300/25-03-06-06-00-00-01-00 Dual-Channel Accelerometer Vibration Monitoring Module – Detailed Product Description

I. Product Overview  

The Bently 3300/25-03-06-06-00-00-01-00 is a dual-channel accelerometer monitoring module from the Baker Hughes (formerly GE Bently Nevada) 3300 series TSI (Turbine Supervisory Instrumentation) system, specifically designed for online monitoring of low-frequency to mid-frequency absolute vibration in industrial large rotating machinery such as machine casings, bearing housings, gearboxes, and equipment foundations. As a standard functional unit within the 3300 series, this module features a dual-channel design with identical measurement ranges, compatible with standard piezoelectric accelerometers. It integrates signal conditioning, filtering, alarm output, hardware self-diagnosis, and system bus communication functions. Supporting hot-swappable installation into standard 19-inch racks, it can be mixed and matched with other 3300 series modules in cabinet configurations. Widely used in thermal power, nuclear power, petrochemicals, metallurgy, air separation, and other industries, this module provides vibration condition monitoring, early fault detection, and safety protection for critical equipment including steam turbines, gas turbines, centrifugal compressors, large fans, and industrial pump units. Compliant with API 670 industry standards, it serves as a core component of rotating machinery condition monitoring systems.

II. Model Code Explanation (3300/25-AA-BB-CC-DD-EE-FF-GG)  

3300: Bently 3300 series modular TSI platform featuring centralized backplane power supply, rack-mounted installation, and hot-swappable architecture.  

25: Function category code indicating dual-channel accelerometer monitoring.  

03 (AA): Channel A range configuration—0–5g (peak), compatible with standard 100 mV/g piezoelectric accelerometers.  

06 (BB): Channel B range configuration—0–10g (peak), compatible with standard 100 mV/g piezoelectric accelerometers.  

06 (CC): Filter combination setting—high-pass 2.7 Hz / low-pass 1 kHz, suitable for low-to-mid frequency vibration monitoring applications.  

00 (DD): Certification configuration—no special industry certification; standard industrial-grade configuration.  

00 (EE): Isolation configuration—no external isolation components; standard electrical isolation design.  

01 (FF): Relay configuration—single epoxy-sealed alarm relay for hazardous alarm output.  

00 (GG): Output configuration—standard configuration without analog output, focused on monitoring, alarming, and data uploading.

III. Core Features  

1. Dual-Channel Independent High-Precision Vibration Acquisition  

Equipped with two fully independent signal input channels, featuring differentiated ranges—Channel A: 0–5g, Channel B: 0–10g—ideal for measuring low-frequency points with varying vibration intensities (e.g., large equipment foundations, low-speed bearing housings). Compatible with standard industrial piezoelectric accelerometers (100 mV/g sensitivity), operating in zero-peak (0–p) measurement mode. The raw frequency response spans 2.7 Hz to 10 kHz, filtered through a 2.7 Hz high-pass and 1 kHz low-pass filter, enabling effective monitoring within the 2.7 Hz to 1 kHz band. This accurately captures low-frequency fault characteristics such as equipment looseness, foundation resonance, low-speed bearing wear, and structural fatigue. The overall measurement accuracy is ≤±0.5% FS, with a resolution of 0.01 g, capable of detecting minute vibration changes and providing early fault warnings. Real-time monitoring detects sensor disconnection, short circuits, signal overloads, or underloads, ensuring reliable operation even in harsh environments such as dusty, humid, or highly electromagnetic interference-prone conditions.

2. Single-Channel Sealed Relay Alarm Output Each monitoring channel can independently set danger alarm thresholds, supporting local configuration via the front panel or remote configuration through a higher-level system. The alarm delay is adjustable from 0 to 10 seconds, effectively filtering out transient vibration disturbances and preventing false alarms. Equipped with a single-channel epoxy-sealed SPDT relay featuring dustproof, moisture-resistant, and anti-vibration characteristics, the contact rated load is 2A/24VDC. It can directly connect to on-site audio-visual alarms, DCS control systems, PLC logic circuits, or unit emergency shutdown interlock circuits, enabling safe alarm signaling and interlock protection upon vibration exceeding limits.

3. Low-Frequency Optimized Signal Filtering  

An internal fixed filter circuit is integrated, configured as a combination of a 2.7Hz high-pass and 1kHz low-pass filter. The high-pass filter blocks DC components and extremely low-frequency environmental noise, while the low-pass filter eliminates high-frequency electromagnetic interference and mechanical shock disturbances, maximizing retention of low-frequency fault characteristic signals. On-site adjustment of filter parameters via internal jumpers is supported, adapting to frequency characteristics of different low-speed equipment and large foundations, thereby enhancing signal recognition accuracy and specificity.

4. Full-Dimensional Hardware Self-Diagnosis  

The device continuously monitors backplane power supply voltage, internal hardware circuits, signal input loops, filtering units, and relay operation status. Upon detecting abnormalities such as power failure, module hardware faults, sensor wiring issues, or signal anomalies, corresponding status indicator lights (OK/Alarm/Fault) on the front panel immediately illuminate and display fault codes, helping maintenance personnel quickly identify fault locations and types, reducing troubleshooting time. Hot-swappable functionality allows module replacement and maintenance without system downtime, significantly minimizing equipment outage losses.

5. System Integration and Anti-Interference Design  

The metal shielded enclosure provides multiple electrical isolations between internal signal, power, and output circuits. Insulation strength between input and power circuits exceeds 2500VAC, offering excellent resistance to EMI/RFI electromagnetic interference. Seamless integration into the 3300 series backplane bus enables connection with Bentley's System 1 equipment condition management platform, allowing remote uploading of real-time vibration data, alarm status, and fault records for trend analysis, data storage, and diagnostics. Additionally, it supports communication via bus protocols with plant DCS, PLC, SCADA, and other automation systems, integrating into the overall plant automation control framework to meet modern industrial requirements for centralized monitoring and predictive maintenance.

IV. Detailed Technical Specifications  

Measurement and Input Parameters  

Number of Channels: 2 independent measurement channels  

Compatible Sensors: Standard piezoelectric accelerometers, rated sensitivity 100mV/g  

Measurement Range: Channel A 0–5g (peak), Channel B 0–10g (peak)  

Frequency Response: Filtered 2.7Hz–1kHz, original 2.7Hz–10kHz  

Measurement Accuracy: ≤±0.5% FS  

Measurement Mode: Zero-to-peak (0–p)  

Input Impedance: ≥100kΩ  

Electrical Parameters  

Power Supply: -24VDC (±10%), supplied uniformly by the system backplane  

Total Power Consumption: ≤5W  

Relay Output: 1×SPDT epoxy-sealed relay, contact rated load 2A/24VDC  

Electrical Isolation: Insulation strength between input and power circuits ≥2500VAC  

Analog Output: None  

Environmental and Mechanical Parameters  

Operating Temperature: 0°C–+65°C  

Storage Temperature: -40°C–+85°C  

Operating Humidity: 5%–95% (non-condensing)  

Installation Method: 19-inch standard rack-mount slot installation, supports hot-swap  

Dimensions: Approx. 203mm × 330mm × 51mm  

Weight: Approx. 0.85–1kg Protection Level: IP20 (suitable for indoor installation inside control cabinets).

Compliance and Certification  

Industry Standards: Complies with API 670 rotating machinery monitoring and protection standards.  

Electromagnetic Compatibility: CE certified, meeting EN 61000-6-2/4 specifications.  

Environmental Directives: Meets RoHS environmental requirements.

V. Typical Application Scenarios  

Power Industry: Vibration monitoring of large steam turbines, generator foundations, and low-speed bearing housings in thermal and nuclear power plants; early warning for foundation loosening, resonance, and bearing wear.  

Petrochemical Industry: Vibration monitoring of large centrifugal compressors, low-speed process pumps, and heavy-duty motor casings; suitable for dusty, oily, and humid environments to ensure continuous production.  

Metallurgical Industry: Vibration monitoring of large sintering equipment, induced draft fans, and rolling mill gearbox foundations; detects structural looseness, mechanical imbalance, and transmission system faults.  

General Industrial Applications: Used in gas turbines, large pumping stations, air separation units, and low-speed gearboxes; provides low-frequency vibration data for equipment condition assessment, fault analysis, and preventive maintenance.

VI. Installation and Commissioning Guidelines  

Installation Requirements  

Rack Installation: Gently insert the module into an available slot on the 3300 series rack, ensuring the rear connector fully engages. Tighten the panel mounting screws securely to guarantee reliable contact. Reserve sufficient ventilation space around the module to prevent heat buildup that could affect cooling and performance.  

Sensor Installation: Piezoelectric accelerometers must be rigidly mounted at locations with effective vibration transmission on the target equipment. The sensor base should be tightly bonded to the surface being monitored. Use dedicated shielded cables for signal wiring, grounding the shield only at one end within the control cabinet—never ground both ends to avoid circulating interference. Route cables away from high-power motors, inverters, and other strong electromagnetic sources.  

Wiring Standards: Clearly distinguish excitation lines, signal lines, and ground lines during connection. Ensure all terminal connections are securely tightened to eliminate loose or intermittent contacts. For relay output circuits, correctly identify common terminals, normally open contacts, and normally closed contacts. After wiring, repeatedly verify circuit continuity.  

Commissioning Steps  

After powering up the backplane, the module automatically performs a self-check. A steady OK indicator light on the front panel indicates successful hardware self-test. If the fault indicator lights up, check sequentially the power supply, wiring, sensors, and the module itself.  

Based on field equipment operating requirements, use the front-panel buttons to enter the parameter setup interface, set alarm thresholds and delay times for both channels, then save the parameters.  

Verify that the internal filter settings meet low-frequency monitoring needs. Adjustments can be made via internal jumpers if necessary.  

After the equipment is loaded and running, observe whether vibration values from both channels remain stable without abnormal fluctuations, confirming no faults in the sensor circuits.  

Manually simulate over-limit conditions to test relay operation, verifying that alarms and interlock logic function accurately before officially commissioning the module.

VII. Maintenance and Troubleshooting  

Routine Maintenance  

During inspections, monitor the status of the module’s front-panel indicators and real-time vibration readings to confirm no alarms or fault indications.  

Periodically inspect all terminal blocks for signs of looseness, oxidation, dust accumulation, or moisture. Check cable insulation for damage.  

Ensure proper rack ventilation. Clean the module surface regularly with a dry soft cloth. Do not allow liquids or metal debris to enter the device interior.  

Periodic Calibration  

Calibrate the module annually using a professional standard vibration test bench. Verify measured vibration values, alarm thresholds, and relay trip points to ensure accurate and reliable measurement and protection functions. Record and archive calibration data.  

Common Fault Troubleshooting  

OK Indicator Light Off: First check whether the 24V DC power supply on the rack backplane is normal. Re-seat the module to rule out poor contact. If ineffective, diagnose as a module hardware failure and replace the module immediately. Frequent vibration value fluctuations: Check whether the sensor is loose, inspect for broken or short-circuited wiring, verify correct grounding methods, identify and eliminate strong electromagnetic interference sources on-site, and replace sensors or signal cables if necessary.  

Frequent false alarms: Verify that alarm thresholds and delay settings are reasonable, check whether filtering parameters mismatch the equipment's low-frequency vibration characteristics, and optimize shielding measures in wiring.  

No relay alarm output: Inspect relay circuit connections and contact conditions to rule out open circuits or damaged contacts.  

Sensor circuit fault indication: Check continuity of cables section by section, verify sensor integrity, and confirm correct polarity; replace faulty components as needed.  

VIII. Usage Precautions  

This product is a standard industrial non-explosion-proof device and must not be installed or used in flammable or explosive hazardous areas.  

Compatible only with 100 mV/g standard piezoelectric accelerometers. Connecting eddy current sensors, platinum resistance thermometers, thermocouples, or other types of sensors is prohibited, as this may result in measurement failure or hardware damage.  

Designed specifically for monitoring low-frequency absolute vibration of machine housings and structures; it must not be used for shaft vibration or shaft displacement monitoring.  

Do not disassemble module enclosures, modify internal circuits, or replace non-original parts. Unauthorized modifications may cause permanent equipment damage and void warranty service.  

Before performing wiring, maintenance, or disassembly operations, disconnect the main power supply to the rack to prevent electric shock or short-circuit accidents. Never plug in or remove modules or touch internal terminals while the equipment is powered on.  

When storing the equipment for extended periods, remove the module from the rack and place it in a dry, cool, and well-ventilated environment to avoid moisture, high temperatures, and dust accumulation, which can accelerate electronic component aging.