990-04-50-02-05 Vibration Transmitter Overview
When machine vibration threatens uptime, the 990-04-50-02-05 from Bently Nevada delivers a precise, loop-powered signal for continuous monitoring. This 990 Vibration Transmitter accepts one non-contacting 3300 NSv Proximity Probe and extension cable, converting dynamic shaft vibration into a standard 4-20 mA output. Designed for industrial environments, it provides a straightforward interface between your machinery and your control system.
With a full-scale range of 0-4 mils pp (0-100 μm pp) and a system length of 5.0 meters (16.4 feet), this transmitter is ready for many rotating equipment applications. The bulkhead screw mounting simplifies installation, while agency approvals including CSA Division 2, ATEX Zone 0, ATEX Zone 2, and ABS maritime approval support use in hazardous areas.
Key Features and Technical Specifications
The 990-04-50-02-05 offers a set of features that ensure accurate, reliable vibration monitoring. Below are the core specifications extracted from the official datasheet.
- Input: Accepts 1 non-contacting 3300 NSv Proximity Probe and extension cable.
- Power: Requires +12 to +35 Vdc input at the transmitter terminal.
- Output: 4 to 20 mAdc over specified full-scale range in 2-wire configuration.
- Accuracy: Within ±1.5% over specified full-scale range (rated from TEST signal input to voltage across 250 Ω loop resistance).
- Probe Gap: Must be gapped between 0.5 and 1.75 mm (20 and 55 mils) from target.
- Maximum Loop Resistance: 1,000 Ω including cable at 35 Vdc.
- Current Limiting: 23 mA typical.
- 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).
- NOT OK/Signal Defeat: Output goes to less than 3.6 mA within 100 µs after a Not OK condition; restored within 2-3 seconds after removal.
- Weight: 0.43 kg (0.9 lbm).
One distinctive feature is the NOT OK/signal defeat function. If the probe or system detects a fault, the output drops below 3.6 mA within 100 µs, alerting your control system immediately. This fast response helps prevent undetected failures and supports safer machine operation.
Applications and Use Cases
The 990-04-50-02-05 is suitable for monitoring vibration on rotating machinery such as pumps, motors, fans, and compressors. In these applications, continuous vibration data helps identify imbalance, misalignment, or bearing wear early. Consequently, maintenance teams can schedule repairs before minor issues escalate into costly downtime.
Additionally, the transmitter’s hazardous area approvals (CSA Division 2, ATEX Zone 0, ATEX Zone 2, ABS maritime) make it a strong candidate for oil and gas, chemical processing, and marine installations. For example, in an offshore platform, the ABS approval ensures the device meets maritime standards, while the ATEX Zone 0 rating allows installation in potentially explosive atmospheres.
Installation and Setup
Proper installation is critical for accurate vibration measurement. First, mount the transmitter using the bulkhead screws provided (Mounting Option 02). Next, connect the 3300 NSv Proximity Probe and extension cable to the input. Ensure the probe gap is set between 0.5 and 1.75 mm (20 and 55 mils) from the target shaft, as this range is necessary to achieve full-scale output.
Power the transmitter with +12 to +35 Vdc at the terminal. The 2-wire configuration simplifies wiring, and the maximum loop resistance of 1,000 Ω (including cable) at 35 Vdc allows flexible cable runs. For the Proximitor Sensor Output (BNC connector), keep the cable length within 3 meters (10 feet) to maintain signal integrity.
Maintenance and Reliability
To ensure long-term reliability, periodically inspect the probe and cable for damage or wear. Verify that the probe gap remains within the specified range, as thermal expansion or mechanical shifts can alter it. Also, check the loop resistance to confirm it stays below the maximum limit.
Because the 990-04-50-02-05 is a solid-state device, it has no moving parts, which reduces maintenance needs. However, regular calibration checks are recommended to maintain the ±1.5% accuracy specification. Always follow the manufacturer’s manual for detailed procedures.
Comparison with Similar Transmitters
When comparing the 990-04-50-02-05 to other vibration transmitters, several parameters stand out:
- Power Range: +12 to +35 Vdc offers flexibility across different control systems.
- Frequency Response: 5 Hz to 6,000 Hz covers typical machine vibration frequencies.
- NOT OK Response: Sub-100 µs response time is faster than many conventional transmitters.
- Hazardous Area Approvals: ATEX Zone 0 and CSA Division 2 ratings are not standard on all models.
These features make the 990-04-50-02-05 a robust choice for demanding environments where early fault detection is essential.
Support and Availability
The 990-04-50-02-05 is available through AutoDCSTech. Contact our team to confirm stock and lead times. We are ready to help you integrate this vibration transmitter into your monitoring system.
