Product Introduction
When a thrust bearing begins to fail, rapid detection is critical. The Bently Nevada 991-06-70-02-00 Probe Vibration Transmitter provides immediate indication through its Not OK signal defeat feature, dropping output below 3.6 mA within 100 µs to minimize damage and unplanned downtime. This industrial automation module is designed for axial vibration monitoring in rotating machinery, accepting one 3300 NSv proximity probe and delivering a 4-20 mA loop signal.
Technical Specifications
The 991-06-70-02-00 operates over a wide environmental range and delivers consistent performance. Key parameters from the manufacturer include:
| Parameter |
Value |
| Power Input |
+12 to +35 Vdc at transmitter terminal |
| Output Signal |
4-20 mA (2-wire configuration) |
| Loop Accuracy |
±1.5% typical over full scale (250 Ω load) |
| Maximum Loop Resistance |
1,000 Ω at 35 Vdc |
| Current Limiting |
23 mA typical |
| Linear Range (Prox Out) |
0.25 to 1.65 mm |
| Full-Scale Option (-06) |
0.6-0-0.6 mm |
| System Length Option (-70) |
7.0 m (23.0 ft) |
| Mounting |
DIN rail; bulkhead screws included |
| Operating Temperature |
-35°C to +85°C |
| Storage Temperature |
-51°C to +100°C |
| Weight |
0.43 kg (0.9 lb) |
The unit also features non-interacting zero and span adjustments, and a Not OK/Signal Defeat that restores output within 0.1 seconds after fault removal.
Real-World Applications
The Bently Nevada 991-06-70-02-00 is ideal for monitoring axial thrust in steam turbines, compressors, and large pumps. In a petrochemical plant, for instance, the rapid Not OK response alerts operators to abnormal thrust before bearing damage escalates. Similarly, in power generation, the 4-20 mA output integrates seamlessly with DCS and PLC systems for continuous condition monitoring.
Installation & Setup Guidance
Mount the 991-06-70-02-00 on a standard DIN rail. Connect a compatible 3300 NSv proximity probe and extension cable to the input terminal. Wire the 4-20 mA loop in a 2-wire configuration, ensuring supply voltage stays between +12 and +35 Vdc at the terminal. Adjust zero and span using the non-interacting external pots. The bulkhead mounting screws (option 02) provide secure attachment in high-vibration environments.
Maintenance & Reliability
The Bently Nevada 991-06-70-02-00 requires minimal routine care. Periodically check loop resistance (max 1,000 Ω) and verify the Not OK function by simulating a fault condition. Given its robust operating range (-35°C to +85°C), the transmitter tolerates harsh industrial environments. The ±1.5% accuracy ensures reliable data for predictive maintenance programs, reducing unplanned outages.
Selection Guide & Purchasing Advice
Before ordering, confirm your full-scale range (-06 for 0.6-0-0.6 mm) and system length (-70 for 7.0 m). Verify that your probe and cable are 3300 NSv compatible. For bulkhead mounting, the 02 option is included. We recommend sourcing from a trusted supplier like PLC Source PRO (available at ubest101.myshopify.com) to ensure genuine Bently Nevada parts and technical support.