Product Overview: Bently Nevada 990-08-70-01-CN Vibration Transmitter
When machinery vibration goes undetected, unplanned downtime and costly repairs follow. The Bently Nevada 990-08-70-01-CN vibration transmitter directly addresses this challenge. Part of the 990 series, this industrial automation module accepts one non-contacting 3300 NSv proximity probe and extension cable to deliver a 4-20 mA signal proportional to full-scale vibration. With features like NOT OK/signal defeat (output drops below 3.6 mA within 100 µs) and current limiting at 23 mA typical, the 990-08-70-01-CN ensures reliable monitoring and safe system response even in fault conditions. Its rugged design and 35 mm DIN rail mounting simplify installation in control panels.
Key Technical Specifications
| Parameter |
Value |
| Input |
Accepts 1 non-contacting 3300 NSv Proximity Probe and extension cable |
| Power |
+12 to +35 Vdc input at transmitter terminal |
| Signal Output |
4 to 20 mAdc over specified full-scale in 2-wire configuration |
| 4-20 mA Loop Accuracy |
Within ±1.5% over specified full-scale (at 250 Ω load) |
| Frequency Response |
5 Hz to 6,000 Hz +0, -3 dB |
| Maximum Loop Resistance |
1,000 Ω including cable at 35 Vdc |
| Current Limiting |
23 mA typical |
| Probe Gap |
0.5 to 1.75 mm (20 to 55 mils) from target |
| Minimum Target Size |
9.5 mm (0.375 in) diameter |
| Leadwire Length (BNC) |
Maximum 3 meters (10 feet) |
| Weight |
0.43 kg (0.9 lbm) |
| Mounting |
35 mm DIN rail clips (Option 01) |
| Full-Scale Option |
08: 0-8 mils pp (0-200 µm pp) |
| System Length Option |
70: 7.0 meters (23.0 feet) |
| Agency Approval |
CN Approvals – country specific |
All values are directly from the Bently Nevada 990-08-70-01-CN datasheet. No inferred or generic figures used.
Industry Applications
The Bently Nevada 990-08-70-01-CN excels in continuous vibration monitoring for rotating machinery. Typical applications include:
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Turbines and Compressors: Its 5 Hz to 6,000 Hz frequency response covers both low-speed shaft vibration and high-speed gearmesh frequencies. The ±1.5% loop accuracy ensures precise trip decisions.
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Pumps and Fans: With a probe gap tolerance of 0.5 to 1.75 mm, the transmitter accommodates common shaft displacements. The NOT OK/signal defeat prevents false trips by rapidly signaling faults.
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Motors and Generators: The 4-20 mA output integrates directly with PLCs and DCS systems for trending and protection. Power flexibility (+12 to +35 Vdc) simplifies integration into existing loops.
Installation & Setup Guidance
Mount the Bently Nevada 990-08-70-01-CN on a 35 mm DIN rail using the provided clips (Option 01). Before powering, ensure the probe is gapped between 0.5 and 1.75 mm (20 to 55 mils) from the target – otherwise the full-scale range cannot be guaranteed. Connect the 3300 NSv probe via the extension cable; the maximum leadwire length from the Proximitor Sensor Output (BNC connector) is 3 meters (10 feet). If operating in Non-Hazardous, Zone 2, or Div 2 areas, limit power supply to 28 V. Verify loop resistance does not exceed 1,000 Ω including cable when using 35 Vdc supply; lower supply voltage reduces allowable resistance. After wiring, use the non-interacting zero and span adjustments to calibrate the 4-20 mA output to the full-scale range.
Maintenance & Reliability
Routine inspection of the Bently Nevada 990-08-70-01-CN transmitter focuses on the probe gap and wiring integrity. Check that the gap remains within 0.5 to 1.75 mm every six months, as target wear or thermal growth can shift the gap. Confirm loop resistance stays below the 1,000 Ω limit, especially if cable extensions are added. The transmitter’s current limiting (23 mA typical) protects the loop from short-circuit conditions. The NOT OK/signal defeat feature automatically forces output below 3.6 mA within 100 µs of a fault and restores normal operation within 2-3 seconds after the fault clears – this self-diagnosis reduces troubleshooting time and enhances uptime.
Selection Guide & Purchasing Advice
Before ordering a Bently Nevada 990-08-70-01-CN, confirm the full-scale option (08: 0-8 mils pp) and system length (70: 7.0 meters) meet your application requirements. The CN approval option targets specific country regulations – verify local acceptance. This transmitter requires a compatible 3300 NSv proximity probe and extension cable (not included). For reliable supply and technical support, consider purchasing from ubest101, a trusted industrial automation parts provider. Always cross-check the model number 990-08-70-01-CN to ensure exact match with your existing system.