Introduction to the 990-10-70-03-00
When machine vibration threatens uptime, the 990-10-70-03-00 from Bently Nevada provides a reliable, loop-powered solution. 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 signal. Designed for continuous monitoring, it helps you detect developing faults before they cause costly failures.
With a full-scale range of 0-10 mils pp (0-250 μm pp), the 990-10-70-03-00 suits a wide variety of rotating machinery. Its compact, DIN-clip mounting simplifies installation in existing panels. This article explains its key specifications, installation considerations, and maintenance practices, helping you integrate it effectively.
Key Features and Technical Specifications
The 990-10-70-03-00 delivers precise vibration measurement with several notable features:
- Accepts one non-contacting 3300 NSv Proximity Probe and extension cable.
- Requires +12 to +35 Vdc input at the transmitter terminal.
- Provides 4 to 20 mAdc output over the specified full-scale range in a 2-wire configuration.
- Loop accuracy within ±1.5% over the full-scale range, measured from the TEST signal input to the voltage across a 250 Ω loop resistance.
- Maximum loop resistance of 1,000 Ω including cable at 35 Vdc.
- Current limiting at 23 mA typical.
- Non-interacting external zero and span adjustments.
- Signal output drops to less than 3.6 mA within 100 µs after a Not OK condition, restoring within 2-3 seconds after removal.
- Frequency response from 5 Hz to 6,000 Hz +0, 3 dB.
- Minimum target size of 9.5 mm (0.375 in) diameter.
- Maximum leadwire length of 3 meters (10 feet) for the Proximitor Sensor Output (BNC connector).
One distinctive spec is the fast Not OK response. The output goes below 3.6 mA within 100 µs, enabling rapid alarm activation. This speed helps protect machinery by alerting operators to sensor faults immediately.
Applications and Use Cases
The 990-10-70-03-00 is ideal for monitoring vibration on pumps, fans, motors, and other rotating equipment. Its 4-20 mA output integrates easily with PLCs, DCS, and SCADA systems. For example, in a continuous process plant, the transmitter can feed vibration data to a control room, allowing operators to trend changes and schedule maintenance proactively.
Because it accepts a 3300 NSv probe, it is suitable for retrofit projects where existing proximity probes are in place. The DIN clip mounting simplifies installation in new or existing cabinets.
Installation and Setup
Proper installation ensures accurate readings. Mount the transmitter using the provided DIN clips and screws (Mounting Option 03). Connect the 3300 NSv probe and extension cable to the input. 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.
Set the probe gap between 0.5 and 1.75 mm (20 and 55 mils) from the target to achieve full-scale range. Use the non-interacting zero and span adjustments to calibrate the output. Ensure the target size is at least 9.5 mm (0.375 in) diameter. Keep the leadwire length within 3 meters (10 feet) for the Proximitor Sensor Output.
Maintenance and Reliability
Regular inspection of the probe and cable is essential. Check for physical damage, loose connections, and proper gap. Verify the output signal periodically against a known vibration source. Because the transmitter is loop-powered, it has minimal moving parts, contributing to long-term reliability.
Monitor the Not OK signal to detect sensor faults quickly. The fast response (less than 3.6 mA within 100 µs) ensures that any failure is immediately visible to the control system. Keep the unit clean and free from excessive moisture or contaminants.
Troubleshooting Common Issues
If the output is not within the expected range, check the probe gap first. An incorrect gap can cause non-linear readings. Verify the supply voltage is within +12 to +35 Vdc. Ensure the loop resistance does not exceed 1,000 Ω. If the output goes below 3.6 mA, a Not OK condition exists—check the probe and cable for faults.
For zero and span issues, use the external adjustments. If the problem persists, consult the Bently Nevada manual or contact AutoDCSTech for support.
Compatibility and Integration
The 990-10-70-03-00 works with Bently Nevada 3300 NSv proximity probes and extension cables. Its 4-20 mA output is universally accepted by most control systems. The DIN clip mounting fits standard DIN rails. No special software is required for basic operation.
Product Support and Availability
The 990-10-70-03-00 is available through AutoDCSTech. For technical assistance or to verify lifecycle status, contact AutoDCSTech. Please confirm current availability before ordering.
