The Bently Nevada 990-10-XX-01-00 (Part Number 283278-01) is a high-precision, loop-powered vibration transmitter designed to integrate critical machinery protection into standard Distributed Control Systems (DCS) or Programmable Logic Controllers (PLC). By converting a proximity probe signal into a linear 4-20 mA output, this module eliminates the need for separate monitors in less critical "balance of plant" equipment. It provides continuous machinery protection for centrifugal air compressors, small pumps, and fans, ensuring early detection of shaft vibration and preventing catastrophic mechanical failure.
| Feature | Specification |
| Input Signal | Accepts input from a 3300 NSv Proximity Probe and Extension Cable |
| Output Signal | 4-20 mA DC, proportional to peak-to-peak shaft vibration |
| Power Requirement | 12 to 35 Vdc (Loop-powered) |
| Scale Range | 0 to 100 µm (4 mil) or 0 to 125 µm (5 mil) peak-to-peak (Configurable) |
| Frequency Response | 10 Hz to 1,000 Hz (600 cpm to 60,000 cpm) ± 10% |
| Operating Temperature | -35°C to +85°C (-31°F to +185°F) |
| Mounting | 35mm DIN rail or G-type rail |
| Linear Range | 0.25 to 1.25 mm (10 to 50 mils) |
The alphanumeric suffixes in the Bently Nevada 990 series determine the specific configuration for scale range and hazardous area approvals. Here is the breakdown for this specific module:
990: Series designation for the Vibration Transmitter.
10: Specifies the Full-scale Range. "10" typically denotes a 0-100 µm (4 mil) peak-to-peak range.
XX: Represents the Approvals Option. (e.g., 01 for ATEX/IECEx/CSA hazardous area ratings, or 00 for no approvals required).
01: Indicates the Mounting Option. "01" signifies standard 35mm DIN rail clips are included.
00: Represents Reserved/Special Options or standard factory configuration.
283278-01: The specific internal part number/orderable hardware ID for the 990 series transmitter.
Proper installation is critical to avoid ground loops and signal interference. Follow these expert recommendations:
Probe Clearance: Ensure the 3300 NSv probe is gapped correctly within the linear range (typically centered at -9.0 Vdc).
Wiring Termination:
Terminal 1 & 2: Loop Power (+) and (-). Connect to your DCS/PLC 24V analog input card.
Terminal 3 & 4: Prox Probe Signal. Ensure the shield is grounded only at the system end to prevent noise.
BNC Connector: Use the front-facing BNC port for temporary connection to a 3500 rack or portable data collector for diagnostic waveform analysis.
Environmental Shielding: Always install the 990 transmitter in an IP54 or higher rated enclosure if the environment is prone to moisture or conductive dust.
Q: Can I use the 990-10 with a standard 3300 XL 8mm probe?
A: No. The 990 Vibration Transmitter is specifically calibrated for use with the 3300 NSv (Near Surface) proximity probe system. Using an 8mm probe will result in incorrect scale factors.
Q: Does this module require a separate Proximitor?
A: No. The 990 module functions as both the driver (Proximitor) and the transmitter. It connects directly to the probe/cable and outputs a 4-20 mA signal.
Q: How do I verify the calibration in the field?
A: You can measure the voltage at the "PROX" and "COM" terminals. The DC voltage should correspond to the physical gap, while the AC component represents the vibration signal.
