Product Overview: Bently Nevada 991-06-70-01-05 Probe Vibration Transmitter
When axial thrust monitoring demands high reliability and rapid fault response, the Bently Nevada 991-06-70-01-05 Probe Vibration Transmitter delivers precise 4-20 mA signals for turbomachinery protection. This industrial automation module accepts a 3300 NSv proximity probe and converts shaft position into a linear current output. Designed for DIN rail mounting, the 991-06-70-01-05 includes agency approvals for hazardous locations (CSA Division 2, ATEX Zone 0/2, ABS maritime) and operates from +12 to +35 Vdc.
Technical Specifications and Performance
The Bently Nevada 991-06-70-01-05 offers a linear range of 0.25 to 1.65 mm for proximity output, supporting 0.6-0-0.6 mm or 25-0-25 mils current loop ranges. Key parameters include:
| Parameter |
Value |
| Output Signal |
4-20 mA (2-wire) |
| Power Supply |
+12 to +35 Vdc at transmitter terminal |
| Accuracy |
±1.5% typical over full-scale range |
| Maximum Loop Resistance |
1000 Ω at 35 Vdc |
| Current Limiting |
23 mA typical |
| Operating Temperature |
-35°C to +85°C |
| Storage Temperature |
-51°C to +100°C |
| Weight |
0.43 kg (0.9 lbm) |
| Zero/Span Adjustment |
Non-interacting external |
Industrial Applications: Axial Thrust Monitoring
The 991-06-70-01-05 monitors axial shaft position in steam turbines, compressors, pumps, and large motors. Its 4-20 mA output integrates directly with PLCs, DCS, and vibration monitoring systems. The 0.6-0-0.6 mm full-scale option suits common thrust bearing clearances. In a typical installation, the Bently Nevada 991-06-70-01-05 connects to a 3300 NSv probe, providing continuous feedback to prevent rotor-to-stator contact.
Installation and Mounting Guide
Mount the 991-06-70-01-05 on a standard 35 mm DIN rail using the supplied clips (option 01). Connect the proximity probe and extension cable to the input terminals. Wire the 4-20 mA loop in a 2-wire configuration with a supply voltage between +12 and +35 Vdc at the transmitter. The non-interacting zero and span potentiometers allow calibration without affecting each other. Ensure ambient temperature remains within -35°C to +85°C for reliable operation.
Troubleshooting and Signal Integrity
The Bently Nevada 991-06-70-01-05 includes a Not OK/Signal Defeat feature that forces output below 3.6 mA within 100 µs when a probe fault occurs. This rapid response enables immediate shutdown logic. After the fault clears, output restores within 0.1 seconds. Common issues include incorrect supply voltage or loop resistance exceeding 1000 Ω at 35 Vdc. Verify probe gap and cable integrity. The 23 mA current limiting protects against short circuits.
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