Features:
- Direct Bridge Connecting 3300 NSv Proximity Probes to DCS/PLC Control Systems
- Integrates Eddy Current Signal Conditioning with Proportional 4-20 mA Output
- Delivers Continuous Shaft Vibration Monitoring in Tight-Clearance Machinery Environments
The Bently Nevada 990-04-70-02-00 Vibration Transmitter functions as a two-wire, loop-powered signal conditioner, providing continuous machinery protection without requiring a dedicated monitor rack. It continuously converts raw high-frequency signals from a 3300 NSv proximity probe into a standard 4 to 20 mA analog output, scaled specifically to a full-scale vibration range of 0-4 mils peak-to-peak (0-100 μm pp). This proportional current signal is transmitted directly over the loop to control system inputs, enabling automated alarm logic and trend tracking for rotating equipment. The integrated design simplifies field wiring and lowers total installation cost compared to multi-channel rack monitoring architectures.
The 990-04-70-02-00 serves a vital protection function for rotating machinery with minimal physical space, such as small centrifugal air compressors, high-speed pumps, and industrial motors. By pairing with the compact 3300 NSv transducer system calibrated to a 7.0-meter (23.0-foot) total system length, the transmitter accurately tracks shaft vibration in tight clearance areas. Designed for simple mechanical integration, this model features factory bulkhead mounting screws (Option -02) for direct surface or panel installation, while its potted enclosure allows reliable operation in high-humidity environments up to 100% condensing.
To ensure high system integrity and avoid false trips, the 990-04-70-02-00 incorporates a built-in Not OK / Signal Defeat circuit. During regular operation, the transmitter continuously evaluates the integrity of the connected probe, extension cable, and field connections. If the system detects a field wiring fault, loose connection, or damaged proximity probe, it automatically clamps the loop current output low rather than spiking high, suppressing false alarms in the connected control system. Additionally, dynamic diagnostic signals remain accessible via non-isolated PROX OUT terminals and a dedicated coaxial connector, allowing field technicians to inspect raw waveform data and gap voltages without interrupting the primary current loop.
The 990-04-70-02-00 Bently Nevada Vibration Transmitter may still be available for purchase and support from Apter Power beyond End-Of-Life (EOL) by the manufacturer (OEM).
Bently Nevada 990-04-70-02-00 Vibration Transmitter 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 990-04-70-02-00 Vibration Transmitter Specs
General
- Manufacturer Bently Nevada
- Model 990-04-70-02-00
- Condition New Original ready stock
- Product Family 990-04-70-02-01,990-04-70-02-05
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.
- OEM Equipment Integration: Widely used by manufacturers of centrifugal air compressors, small pumps, motors, or industrial fans. It provides a direct 4 to 20 mA signal directly into their package control system.
- Distributed Control Interfacing: Directly interfaces with standard process control systems, such as Distributed Control Systems (DCS), Programmable Logic Controllers (PLCs), and SCADA platforms. This removes the need for standalone, dedicated rack-based machinery protection monitors.
- Confined Space Monitoring: Optimized for use with the 3300 NSv Proximity Probe. This probe system is purpose-built for installations with minimal side-clearance or very tight target areas common in small fluid machinery.
- Real-time Diagnostic Troubleshooting: Maintenance technicians use the integrated PROX OUT and COM terminals or the coaxial connector to capture dynamic gap voltage and vibration waveforms for deep machinery analysis without interrupting the control loop.
- False Alarm Prevention (Not OK Circuit): Features an onboard Not OK/Signal Defeat circuit. If the companion proximity probe goes faulty, short-circuits, or experiences a loose cable connection, the circuit automatically restricts output. This prevents false high-vibration trips on the control system.
- Power-Up Line Stability: Contains a Power-up Inhibit circuit. This keeps the output signal clamped during initial startup, preventing transient voltage spikes from causing unintended alarm trips in the PLC/DCS.
- Environmental Protection: Built with a fully potted construction. It withstands up to 100% condensing relative humidity environments, protecting internal electronics from corrosive environments or moisture.
- Regulatory Compliance: The specific -00 suffix variant is the baseline option where specialized explosion-proof or intrinsically safe certifications are not required. (Note: For hazardous areas, alternative options like the -CN for ATEX/IECEx/NEPSI or -05 for CSA Class I Div 2 are available).
- Non-Interacting Adjustments: Features individual, non-interacting zero and span potentiometers positioned directly beneath the outer product label. Adjusting the zero pot does not change the span setting, making field calibration fast and straightforward.
- System Matching: Calibration must match its structural hardware limits. For the 990-04-70-02-00, it is matched to a 7.0-meter system length (combining probe and extension cable). Changing extension cables to unmatched lengths will throw off the calibration scale factor.
- Loop Output Verification: Features a dedicated Test Input pin. Technicians can inject a simulated waveform using a standard function generator to quickly verify that the 4-20 mA loop outputs the correct corresponding peak-to-peak units to the control room.
- Diagnostic Translation: The native PROX OUT signal is non-isolated. If connecting the transmitter directly to AC-powered analyzer equipment, the use of a Bently Nevada 990/991 Test Adapter is recommended to invert the phase and properly isolate the signal.
