Introducing the Bently Nevada 990-08-70-03-CN Vibration Transmitter
When machine vibration threatens uptime, the 990-08-70-03-CN from Bently Nevada delivers precise, real-time data. This 990 Vibration Transmitter accepts one non-contacting 3300 NSv Proximity Probe and extension cable, converting shaft vibration into a standard 4-20 mA signal. It is designed for continuous operation in industrial environments, including non-hazardous, Zone 2, and Div 2 hazardous areas.
Key Features and Technical Specifications
The 990-08-70-03-CN offers a full-scale range of 0-8 mils pp (0-200 μm pp), making it suitable for measuring moderate vibration levels. It requires +12 to +35 Vdc input at the transmitter terminal, with a maximum loop resistance of 1,000 Ω including cable at 35 Vdc. The current limiting is 23 mA typical, and the 4-20 mA signal output operates in a 2-wire configuration.
- Full-scale range: 0-8 mils pp (0-200 μm pp)
- Input: Accepts 1 non-contacting 3300 NSv Proximity Probe and extension cable
- Power: +12 to +35 Vdc input at the transmitter terminal
- Maximum loop resistance: 1,000 Ω including cable at 35 Vdc
- Current limiting: 23 mA typical
- Signal output: 4-20 mAdc over specified full-scale range
- Loop accuracy: Within ±1.5% over specified full-scale range
- Frequency response: 5 Hz to 6,000 Hz +0, 3 dB
- Minimum target size: 9.5 mm (0.375 in) diameter
- Leadwire length: Maximum 3 meters (10 feet) for Proximitor Sensor Output (BNC connector)
Addressing Common Pain Points
Vibration monitoring systems often face challenges such as signal drift, false alarms, and difficult installation. The 990-08-70-03-CN mitigates these issues with non-interacting external zero and span adjustments. This allows for precise calibration without affecting other parameters, reducing setup time and improving measurement accuracy.
Another common issue is the need for fast response to fault conditions. The transmitter's NOT OK/signal defeat function drives the output to less than 3.6 mA within 100 µs after a Not OK condition occurs. This rapid response enables immediate shutdown or alarm activation, protecting machinery from potential damage.
Installation and Setup
Proper installation is critical for accurate vibration measurement. The 990-08-70-03-CN comes with a system length option of 7.0 meters (23.0 feet) and a mounting option of DIN clips and screws. The probe must be gapped between 0.5 and 1.75 mm (20 and 55 mils) from the target to ensure full-scale range. Follow the manufacturer's guidelines for mounting and wiring to avoid errors.
For hazardous area installations, the transmitter is approved for non-hazardous, Zone 2, or Div 2 locations. Ensure that the power supply is set to 28 V as specified, and verify that the loop resistance does not exceed 1,000 Ω at 35 Vdc.
Maintenance and Reliability
Regular inspection of the transmitter and probe is recommended to maintain reliable operation. Check for any physical damage, loose connections, or contamination that could affect performance. The transmitter's robust design and 23 mA current limiting help protect against overcurrent conditions, extending service life.
Routine verification of the 4-20 mA output against a known vibration source can confirm accuracy. If the output deviates beyond the ±1.5% specification, recalibrate using the external zero and span adjustments.
Compatibility and Integration
The 990-08-70-03-CN integrates seamlessly with existing Bently Nevada monitoring systems. It accepts a 3300 NSv Proximity Probe, ensuring compatibility with standard proximity probe installations. The 4-20 mA output can be connected to PLCs, DCSs, or standalone monitors, providing flexibility in system design.
For applications requiring country-specific approvals, the CN option ensures compliance with local regulations. Always verify the approval requirements for your region before installation.
Troubleshooting Common Issues
If the output signal is not within the expected range, check the probe gap and ensure it is within 0.5 to 1.75 mm. Verify that the power supply is providing +12 to +35 Vdc and that the loop resistance is within limits. If the output goes below 3.6 mA, a Not OK condition may be present; check the probe and cable connections.
For persistent issues, consult the official Bently Nevada documentation or contact AutoDCSTech for technical support.
Product Support and Availability
The 990-08-70-03-CN is available through AutoDCSTech. Please verify current lifecycle status and availability with AutoDCSTech before ordering. For technical questions, contact our team for prompt assistance.
