990-08-50-02-01 Vibration Transmitter Overview
When rotating machinery health is critical, the Bently Nevada 990-08-50-02-01 provides a reliable vibration monitoring solution. 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. With a full-scale range of 0-8 mils pp (0-200 μm pp), it suits many industrial rotating assets.
The transmitter requires +12 to +35 Vdc input at the terminal, making it flexible for various power supplies. Its 4-20 mA output operates in a 2-wire configuration, simplifying wiring and reducing installation cost. The unit is made in the U.S.A. and carries CSA Division 2 approval for hazardous area locations.
Key Features and Technical Specs
- Full-scale range: 0-8 mils pp (0-200 μm pp) — matches the 08 option.
- System length: 5.0 meters (16.4 feet) — option 50.
- Mounting: Bulkhead screws — option 02.
- Agency approval: CSA Division 2 — option 01.
- 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 in 2-wire configuration.
- Loop accuracy: Within ±1.5% over full-scale range, measured from TEST signal to voltage across a 250 Ω load.
- Probe gap: Must be gapped between 0.5 and 1.75 mm (20 and 55 mils) from target.
- 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).
- Weight: 0.43 kg (0.9 lbm).
One distinctive spec is the fast Not OK response: the signal output drops to less than 3.6 mA within 100 µs after a Not OK condition, and restores within 2-3 seconds after removal. This rapid response helps protect downstream control systems from false readings, reducing downtime and maintenance costs.
Cost-Efficiency and ROI
By converting raw vibration data into a standard 4-20 mA loop, the 990-08-50-02-01 eliminates the need for expensive dedicated vibration monitoring systems. Its 2-wire configuration reduces cabling and installation labor. The ±1.5% accuracy ensures reliable data, preventing costly false alarms and unscheduled shutdowns. The CSA Division 2 approval avoids the need for explosion-proof enclosures in many hazardous areas, saving significant capital expense.
Applications and Use Cases
This transmitter is ideal for monitoring fans, pumps, motors, and other rotating equipment where shaft vibration indicates mechanical condition. For example, in a petrochemical plant, the 990-08-50-02-01 can be mounted near a pump bearing housing, providing continuous 4-20 mA signal to a PLC or DCS. Its fast Not OK response helps trigger alarms quickly, minimizing damage. The 0-8 mils pp range suits machines with moderate vibration levels, and the 5-meter system length allows flexible probe placement.
Installation and Setup
Mount the transmitter using the bulkhead screws (option 02). Connect the 3300 NSv 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 to achieve full-scale range. Power the transmitter with +12 to +35 Vdc at the terminal. The 4-20 mA output connects in a 2-wire loop, with maximum loop resistance of 1,000 Ω at 35 Vdc. For hazardous areas, follow CSA Division 2 installation guidelines.
Maintenance and Reliability
Routine inspection should focus on the probe gap and cable integrity. Verify the transmitter's output responds correctly to vibration changes. Because the unit is designed for continuous operation, periodic checks every 6-12 months are recommended. The fast Not OK response ensures that any internal fault is quickly communicated, reducing the risk of undetected failures. Always follow the manufacturer's manual for detailed maintenance procedures.
Compatibility and Integration
The 990-08-50-02-01 works with any 3300 NSv Proximity Probe and extension cable. Its 4-20 mA output integrates directly with PLCs, DCS, and SCADA systems. The CSA Division 2 approval makes it suitable for Zone 2 or Div 2 hazardous locations. For maximum performance, use a power supply of 28 V (as noted in the data) to ensure adequate loop voltage.
Troubleshooting and Common Issues
If the output goes below 3.6 mA, a Not OK condition is present. Check the probe gap and cable connections. Ensure the power supply is within +12 to +35 Vdc. If the loop resistance exceeds 1,000 Ω, the output may be limited. Verify the target size is at least 9.5 mm diameter. For persistent issues, consult the official Bently Nevada documentation or contact AutoDCSTech.
Product Support and Availability
The Bently Nevada 990-08-50-02-01 is available through AutoDCSTech. Please verify current lifecycle status and availability before ordering. Contact AutoDCSTech for pricing and lead times.
