Description
I. Product Overview
Bently Nevada 3500/40M is a 4-channel proximity transducer monitoring module for the Bently Nevada 3500 series machinery protection system, the core acquisition card of TSI turbine supervisory instrumentation system. It is specially matched with the 3300XL series eddy current displacement probes to condition, collect, calculate the shaft process parameters of rotating equipment and judge threshold alarms. It provides protection trip logic for unit safety interlock, and transmits real-time process data to DCS and upper monitoring systems to meet the dual requirements of equipment safety protection and predictive operation and maintenance.The module supports channel grouping in pairs, which can be flexibly configured for five measurement functions: radial vibration, axial thrust displacement, differential expansion, shaft eccentricity and REBAM rolling element bearing condition analysis. With SIL2 safety certification and compliance with API 670 industry standards, it integrates complete channel fault self-diagnosis functions to accurately identify probe open circuit, abnormal gap, signal short circuit and other faults. It is widely used in condition monitoring and safety protection of key rotating equipment in thermal power, chemical, oil & gas, metallurgy and other industries.
II. Hardware Structure and Composition
1. High-precision Signal Conditioning and Acquisition Unit
It integrates differential signal amplification, anti-aliasing filtering and 24-bit high-precision AD conversion circuits, which perform impedance matching and noise reduction shaping on the -24V DC bias gap signal output by eddy current probes, and converts gap voltage into displacement according to preset sensitivity. It can output multi-dimensional monitoring parameters such as full-scale amplitude, 1X/2X frequency phase and original waveform data. Built-in multi-order digital filtering can avoid data jump caused by power grid and frequency converter interference, with measurement accuracy up to ±0.33% of full scale.
2. Four-channel Isolated Input Loop
Four mutually independent differential isolated input channels with input impedance greater than 100kΩ. Inter-channel electrical isolation prevents single-channel sensor line faults from interfering with other monitoring points. Two hardware versions are available: internal terminal and intrinsically safe barrier external terminal. The explosion-proof version can be directly applied to field wiring in hazardous Zone 1 and Zone 2. Each channel can independently configure measurement type, alarm delay and two-stage alarm thresholds of Alert pre-alarm and Danger trip.
3. Front Panel Status Indicator Unit
Three groups of LED indicators are equipped on the front panel: steady green OK light indicates normal module power supply and firmware operation; flashing TX/RX light represents normal data interaction between the module and rack backplane and communication modules; lit Bypass light means the module or corresponding channel is under bypass shielding. Maintenance personnel can quickly judge module operation, communication and bypass faults through indicators without software commissioning.
4. Rack Backplane Bus Interaction Unit
The full-height gold finger interface is inserted into the standard 19-inch rack backplane of the 3500 series. High-speed backplane bus realizes data interaction with power supply, communication, relay and keyphasor modules, uploading real-time monitoring values, fault diagnosis codes and waveform data, and downloading configuration parameters and bypass instructions. It supports TMR triple modular redundant architecture to meet fault-tolerant protection requirements of high-safety units.
5. Industrial Protective Rack Mounting Structure
Full-height standard rack card structure with anti-loose panel locking screws, whole-machine three-proof conformal coating and metal shielded housing to suppress spatial electromagnetic radiation interference. The rear part integrates terminal wiring interface for standard access of sensor coaxial cables, compatible with 8-slot and 14-slot 3500 racks.
III. Technical Specifications
(1) Electrical Parameters
- Input Specification: 4-channel differential eddy current probe input, compatible with 3300XL series sensors, standard input impedance 10kΩ, 50kΩ for single channel under TMR architecture
- Optional Sensitivity: Vibration/Displacement: 3.94mV/μm, 7.87mV/μm; Differential Expansion: 0.394mV/μm, 0.787mV/μm; REBAM: 40mV/μm, 80mV/μm
- Frequency Response: 0.7Hz～1kHz, software configurable low-pass filter
- Power Consumption: Typical 7～7.7W, powered by rack backplane 24VDC
- Alarm Configuration: Two-stage programmable alarms (pre-alarm, trip) per channel, supporting alarm delay to avoid misoperation
- Analog Output: Configurable 4～20mA, 0～10V standard signals for upper system transmission
(2) Environmental Parameters
- Operating Temperature: -30℃～+65℃; Storage & Transportation Temperature: -40℃～+85℃
- Relative Humidity: 5%～95%RH, non-condensing, no corrosive gas and conductive dust
- Vibration Resistance: Compliant with IEC 60068 industrial vibration and shock standards
(3) Mechanical Parameters
- Mounting: Full-height slot of standard 19-inch 3500 rack
- Overall Dimensions: 241.3mm×24.4mm×241.8mm
- Net Weight: Approx. 0.91kg
- Fixing: Panel locking screw, integrated shielded grounding
IV. Product Functions and Features
Flexible Dual-group Channel Configuration for Multi-type Shaft Parameter MonitoringChannels are grouped in pairs, two groups can be independently set for different measurement types, realizing combined monitoring such as radial vibration + axial displacement, differential expansion + shaft eccentricity on one single module. Built-in REBAM bearing diagnosis algorithm can identify early faults such as rolling bearing fatigue and pitting, supporting predictive maintenance.
Full-channel Intelligent Fault Diagnosis to Prevent Mis-protection and Missing Protection
It monitors probe gap, cable short circuit, open circuit and preamplifier power supply abnormality online in real time. Once a line fault is detected, the corresponding channel will be locked with fault code uploaded, and the channel alarm can be shielded to avoid unit trip caused by line failure, meanwhile fault records are retained for maintenance tracing.Multi-level Anti-misalarm Mechanism Adaptable to Complex Working Conditions
Software-configurable alarm delay and digital filtering can filter transient data over-limit caused by unit startup/shutdown and grid disturbance to distinguish real mechanical faults from process transient fluctuations. The bypass maintenance mode allows probe inspection and replacement without unit shutdown during maintenance.Dual Data Output for Safety Interlock and Fault Diagnosis
Hard contact trip signals are output via backplane linked with 3500/32 relay modules to access SIS safety interlock system for emergency shutdown; full-spectrum values, frequency phase and waveform data are uploaded to DCS and vibration analysis system for fault diagnosis such as rotor unbalance and misalignment.Full System Compatibility for Convenient Spare Part Replacement
It is fully compatible with all 3500 series racks and supporting modules. The same model supports hot swapping, and can be put into operation after downloading original configuration parameters. Three-proof wide-temperature design ensures long-term stable operation in harsh industrial control cabinets with low routine maintenance cost.V. Application Scenarios
- TSI safety monitoring and interlock protection for steam turbine generator sets and feedwater pump turbines in thermal and gas power plants, covering radial vibration, axial displacement, differential expansion and shaft eccentricity.
- On-line monitoring of shaft vibration and thrust displacement of ethylene, propylene and recycle hydrogen centrifugal compressors in petrochemical plants to prevent severe equipment accidents such as surge and rotor-stator friction.
- Condition monitoring of bearing vibration and shaft displacement for blast furnace blowers, large fans and high-speed pumps in metallurgy and cement industries for early fault warning.
- Rotating equipment monitoring in hazardous areas of offshore oil & gas platforms and long-distance pipeline compressor stations, adopting intrinsically safe barrier version to meet explosion-proof requirements.
- Modernization renovation projects including 3500 system overhaul, measuring point expansion and faulty acquisition card replacement.
