Product Overview
The Bently Nevada 991-06-70-02-CN is a rugged Probe Vibration Transmitter designed for continuous monitoring of axial thrust in rotating machinery. This Industrial Automation Module integrates with a 3300 NSv proximity probe to deliver a precise 4-20 mA output proportional to shaft position. Its DIN rail mount design simplifies installation in control panels. With a full-scale option of 0.6-0-0.6 mm and a system length of 7.0 meters (23.0 feet), the 991-06-70-02-CN provides tailored measurement for your specific application.
Technical Specifications Breakdown
The 991-06-70-02-CN is built for accuracy and reliability in harsh environments. Key parameters include:
| Parameter |
Value |
| Output Signal |
4-20 mA (2-wire) |
| Power Supply |
+12 to +35 Vdc |
| Linear Range (Prox Out) |
0.25 to 1.65 mm |
| Accuracy (typical) |
±1.5% of full scale |
| Max Loop Resistance |
1,000 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 lb) |
The 991-06-70-02-CN accepts one non-contacting 3300 NSv proximity probe and extension cable. Its accuracy rating is measured from the TEST signal input to the voltage across a 250 Ω loop resistance. The device features non-interacting zero and span adjustments, ensuring easy calibration.
Industry Applications
This transmitter is ideal for monitoring axial thrust in steam turbines, compressors, and large pumps. For example, in a turbine system where axial displacement must stay within 0.6-0-0.6 mm, the 991-06-70-02-CN provides real-time feedback to the control system. Its Not OK/Signal Defeat feature (<3.6 mA within 100 µs after a fault) prevents false alarms and protects equipment during transient events.
Installation & Setup Guidance
Mount the Bently Nevada 991-06-70-02-CN on a DIN rail within the specified environmental limits. Connect the 3300 NSv probe and extension cable to the input. Wire the 4-20 mA loop in a 2-wire configuration, ensuring power supply is between +12 and +35 Vdc. Verify loop resistance does not exceed 1,000 Ω including cable. Adjust zero and span using the external controls per your application’s full-scale range (e.g., 0.6-0-0.6 mm or 25-0-25 mils). The transmitter automatically enters a Not OK state if probe signal is lost or out of range.
Maintenance & Reliability
Routine maintenance involves verifying probe gap and cable integrity. The 991-06-70-02-CN is built to withstand extreme temperatures and vibration. Its 23 mA current limiting prevents damage from loop faults. For long-term reliability, inspect connections annually and test the Not OK defeat function. The environmental limits (-35°C to +85°C operating) ensure dependable performance in outdoor or high-temperature settings.
Selection Guide & Purchasing Advice
When ordering the Bently Nevada 991-06-70-02-CN, confirm the full-scale option (-06: 0.6-0-0.6 mm), system length (-70: 7.0 meters), mounting option (02: bulkhead screws), and agency approval (CN). Ensure you have a compatible 3300 NSv proximity probe and extension cable. For expert assistance and genuine parts, contact PLC Source PRO (formerly ubest101). All units are made in the U.S.A. and come with specified ordering options.