Product Overview
When vibration monitoring systems fail, unplanned downtime can cost thousands. The Bently Nevada 990-08-70-01-01 990 Vibration Transmitter provides reliable, continuous measurement with built-in fault detection. This industrial automation module accepts one non-contacting 3300 NSv Proximity Probe and delivers a 4-20 mA signal proportional to vibration displacement. Designed for harsh environments, it comes with a CSA Division 2 agency approval.
Technical Specifications
| Parameter |
Value |
| Full-scale Option |
08 – 0-8 mils pp (0-200 μm pp) |
| System Length Option |
70 – 7.0 meters (23.0 feet) |
| Mounting Option |
01 – 35 mm DIN rail clips |
| Agency Approval Option |
01 – CSA Division 2 |
| Input |
Accepts 1 non-contacting 3300 NSv Proximity Probe and extension cable |
| Power |
+12 to +35 Vdc input at the transmitter terminal |
| 4-20 mA Signal Output |
4 to 20 mAdc over specified full-scale range in 2-wire configuration |
| 4-20 mA Loop Accuracy |
Within ±1.5% over specified full-scale range (accuracy rated from TEST signal to voltage across 250 Ω loop resistance; error additional to Prox Out Incremental Scale Factor) |
| Probe Gap |
0.5 to 1.75 mm (20 to 55 mils) from target |
| Maximum Loop Resistance |
1,000 Ω including cable at 35 Vdc |
| Current Limiting |
23 mA typical |
| Zero and Span |
Non-interacting external adjustments |
| NOT OK/Signal Defeat |
Signal goes less than 3.6 mA within 100 μs after a Not OK condition; restores within 2-3 seconds after condition removed |
| Frequency Response |
5 Hz to 6,000 Hz +0, -3 dB |
| Minimum Target Size |
9.5 mm (0.375 in) diameter |
| Leadwire Length (Proximitor Sensor Output BNC) |
Maximum cable distance 3 meters (10 feet) |
| Hazardous Area Locations |
Non-Hazardous, Zone 2 or Div 2 |
| Power Supply (Hazardous Area) |
28 V |
| Weight |
0.43 kg (0.9 lbm) |
Industry Applications
The Bently Nevada 990-08-70-01-01 is ideal for monitoring vibration on rotating machinery such as turbines, compressors, pumps, and fans. Its 4-20 mA output integrates seamlessly with PLCs, DCS, and SCADA systems for continuous condition monitoring. With a frequency response from 5 Hz to 6,000 Hz, it captures both slow-speed and high-speed machine dynamics.
Installation & Setup
Mount the Bently Nevada 990-08-70-01-01 on a 35 mm DIN rail using the included clips. Connect one 3300 NSv Proximity Probe with extension cable to the input. Ensure the probe gap is between 0.5 and 1.75 mm (20 and 55 mils) from the target surface for accurate full-scale range. The maximum cable distance from the Proximitor Sensor Output (BNC connector) is 3 meters (10 feet). Power the transmitter with +12 to +35 Vdc at the terminal. Adjust zero and span using the non-interacting external adjustments.
Troubleshooting Common Issues
The Bently Nevada 990-08-70-01-01 features a NOT OK/signal defeat function: if a fault occurs, the output drops below 3.6 mA within 100 μs. This fast response alerts the control system immediately. Common issues include improper probe gap (must remain within 0.5-1.75 mm), incorrect power supply voltage, or excessive loop resistance (max 1,000 Ω at 35 Vdc). The current limiting (23 mA typical) protects against short circuits. If the output saturates or drifts, check the probe connection and adjust zero/span.
Selection & Purchasing Guide
Before ordering, verify that your system uses a compatible 3300 NSv Proximity Probe and that the full-scale range (0-8 mils pp) meets your vibration monitoring requirements. For Zone 2 or Div 2 hazardous locations, ensure power supply is limited to 28 V. PLC Source PRO offers genuine Bently Nevada parts with fast shipping. Visit our store at ubest101.myshopify.com to purchase the Bently Nevada 990-08-70-01-01.