Introduction to the 990-10-50-03-CN Vibration Transmitter
When rotating machinery experiences vibration, unplanned downtime can follow quickly. The 990-10-50-03-CN from Bently Nevada provides a direct solution by converting proximity probe signals into a standard 4-20 mA output. This makes it a practical choice for continuous vibration monitoring in industrial environments.
This 990 Vibration Transmitter accepts one non-contacting 3300 NSv Proximity Probe and extension cable. It operates with a power input of +12 to +35 Vdc at the transmitter terminal. The unit is manufactured in the U.S.A. and includes a full-scale option of 0-10 mils pp (0-250 μm pp).
Key Features and Technical Specifications
The 990-10-50-03-CN is designed for straightforward integration into existing monitoring systems. Its specifications are summarized below:
| Parameter | Value |
|---|---|
| Full-scale Option | 0-10 mils pp (0-250 μm pp) |
| System Length Option | 5.0 meters (16.4 feet) |
| Mounting Option | DIN clips and screws |
| Agency Approval | Country specific (CN) |
| Input | 1 non-contacting 3300 NSv Proximity Probe and extension cable |
| Power | +12 to +35 Vdc at transmitter terminal |
| Maximum Loop Resistance | 1,000 Ω including cable at 35 Vdc |
| Current Limiting | 23 mA typical |
The 4-20 mA signal output is provided in a 2-wire configuration. Loop accuracy is within ±1.5% over the specified full-scale range, measured from the TEST signal input to the voltage across a 250 Ω loop resistance. This accuracy is in addition to the Prox Out Incremental Scale Factor.
Performance and Reliability
The 990-10-50-03-CN offers a frequency response of 5 Hz to 6,000 Hz (+0, 3 dB). This range covers typical machine vibration frequencies, allowing effective monitoring of rotating equipment.
Signal integrity is maintained through a NOT OK/signal defeat feature. When a Not OK condition occurs, the signal output drops to less than 3.6 mA within 100 µs. After the condition is removed, the output is restored within 2-3 seconds. This rapid response helps protect downstream monitoring systems from false readings.
Zero and span adjustments are non-interacting and external, simplifying calibration. The probe must be gapped between 0.5 and 1.75 mm (20 and 55 mils) from the target to ensure full-scale range. The minimum target size is 9.5 mm (0.375 in) diameter.
Installation and Setup
Mounting the 990-10-50-03-CN is straightforward with the DIN clips and screws option. The system length of 5.0 meters (16.4 feet) provides flexibility in locating the transmitter relative to the probe.
For the Proximitor Sensor Output (BNC connector), the maximum cable distance is 3 meters (10 feet). Ensure that the probe gap is set within the specified range during installation to achieve accurate measurements.
Power supply requirements are flexible: the transmitter accepts +12 to +35 Vdc, with a typical supply of 28 V for hazardous area locations. The maximum loop resistance is 1,000 Ω including cable at 35 Vdc, which must be considered when designing the loop.
Applications and Use Cases
The 990-10-50-03-CN is suitable for vibration monitoring on pumps, fans, motors, and other rotating machinery. Its 4-20 mA output integrates easily with PLCs, DCS, and SCADA systems, enabling continuous monitoring without specialized software.
In predictive maintenance programs, this transmitter helps detect early signs of bearing wear, unbalance, or misalignment. By providing a real-time vibration signal, it supports condition-based maintenance strategies that reduce unplanned downtime.
The compact design and DIN mounting make it ideal for retrofit projects where space is limited. Its country-specific approval (CN) ensures compliance with local regulations.
Maintenance and Reliability
Regular inspection of the probe gap and cable connections is recommended to maintain measurement accuracy. The non-interacting zero and span adjustments allow quick recalibration if drift is observed.
The transmitter's current limiting at 23 mA typical protects the loop from overcurrent conditions. The NOT OK signal defeat feature ensures that fault conditions are clearly communicated, aiding in rapid troubleshooting.
For long-term reliability, follow the manufacturer's guidelines for periodic verification of loop accuracy and probe gap. This helps sustain the ±1.5% accuracy specification over time.
Product Support and Availability
The 990-10-50-03-CN is available through AutoDCSTech. Contact AutoDCSTech for current availability and lifecycle status before ordering. They can provide additional technical documentation and support.
