Bently Nevada 990-04-70-02-00 990 Series 2-Wire Vibration Transmitter
Manufacturer: Bently Nevada
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Part Number: 990-04-70-02-00
Condition：New with Original Package
Product Type: Proximity Sensors
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Country of Origin: USA
Payment:T/T, Western Union
Shipping port: Xiamen
Warranty: 12 months
Bently Nevada 990-04-70-02-00 990 Vibration Transmitter
The Bently Nevada 990-04-70-02-00, also cataloged as the 990-04-70-02-00 2-Wire Vibration Transmitter, operates as a dedicated hardware component for converting eddy-current probe signals into a proportional 4-20 mA current loop within machinery monitoring networks.
Suffix Breakdown & Model Matrix
| Option Code | Designator | Engineering Definition |
|---|---|---|
| Model | 990 | Vibration Transmitter |
| Full-Scale | -04 | 0 to 4 mils pp (0 to 100 um pp) |
| System Length | -70 | 7.0 meters (23.0 feet) |
| Mounting | -02 | Bulkhead screws |
| Agency Approval | -00 | Not required |
Hardware Specifications
| Parameter | Specification |
|---|---|
| Model | 990-04-70-02-00 |
| Brand | Bently Nevada |
| Origin | United States |
| Weight | 0.82 kg (Shipping weight 2.0 kg) |
| Dimensions | 100 mm x 74 mm x 53.3 mm |
| Operating Temp | Standard industrial ambient range |
| Power Consumption | Loop powered, +12 to +35 VDC input |
| Full-Scale Range | 0 to 4 mils pp (0 to 100 um pp) |
| Output Signal | 4-20 mA DC, 2-wire proportional |
| Accuracy | +/- 1.5% of full-scale (excluding probe factor) |
| Probe Gap Target | 0.5 to 1.75 mm (20 to 55 mils) |
| Loop Resistance | Maximum 1,000 ohms at 35 Vdc |
| Signal Defeat | Drops below 3.6 mA within 100 us under Not OK condition |
Eddy-Current Probe Scaling & Rotor Dynamics Validation
The unit operates directly with a 3300 NSv proximity probe system over a total electrical system length of 7.0 meters. Correct operation relies on precise eddy-current probe scaling to establish an accurate gap voltage validation targeting -10 VDC at the linear center of the probe range. Internal signal conditioning processes high-frequency rotor dynamics and provides cross-talk suppression between adjacent channels before driving the isolation circuit to send the 4-20 mA signal to the DCS or PLC.
Frequently Asked Questions
Q: How does the transmitter handle system fault detection during probe lead disconnects?
A: The internal logic executes a rapid fault response that drops the loop current output below 3.6 mA within 100 us when a Not OK condition occurs, allowing downstream control systems to detect wire breaks immediately.
Q: What mounting configuration does the -02 option suffix specify for hardware installation?
A: The -02 suffix designates a bulkhead screw mounting chassis designed for direct mechanical fastening onto flat enclosure surfaces using hardware fasteners rather than DIN-rail clips.
Field Installation Guidelines
Mount the transmitter chassis firmly onto a flat surface using the designated bulkhead mounting holes. Ensure that the 3300 NSv probe and extension cable total length equals exactly 7.0 meters to maintain accurate eddy-current probe scaling. Route coaxial probe leads in isolated, grounded conduit away from high-voltage motor power leads to prevent cross-talk noise coupling. Terminate the 2-wire 4-20 mA loop cable using twisted-pair shielded wire, connecting the cable shield to the main plant earth ground at a single point inside the control panel.