Product Introduction
When axial thrust monitoring failures lead to costly unplanned downtime, the Bently Nevada 991-06-70-03-CN Probe Vibration Transmitter provides a reliable solution. This industrial automation module is a thrust transmitter designed for continuous measurement of shaft axial position. It accepts one non-contacting 3300 NSv proximity probe and extension cable, converting probe gap changes into a 4-20 mA signal proportional to the full-scale range. The 991-06-70-03-CN is part of the 991 series, offering configuration options: full-scale -06 (0.6-0-0.6 mm), system length -70 (7.0 meters), mounting option 03 (DIN clips and screws), and agency approval CN for country-specific approvals. Built in the U.S.A., it ensures robust performance in critical rotating machinery applications.
Technical Specifications Breakdown
The Bently Nevada 991-06-70-03-CN delivers key performance parameters essential for precise axial position measurement. Its 4-20 mA loop accuracy is within ±1.5% over the specified full scale range (typical), measured from the TEST signal input to the voltage across a 250 Ω loop resistance. The maximum loop resistance is 1,000 Ω including cable at 35 Vdc. Current limiting is 23 mA typical, protecting the loop. The transmitter requires +12 to +35 Vdc input at the transmitter terminal. For linear range, it operates from 0.25 to 1.65 mm for Prox Out, suitable for 0.6-0-0.6 mm or 25-0-25 mils current loop linear ranges. Zero and span adjustments are non-interacting external adjustments. The Not OK/signal defeat function forces the output below 3.6 mA within 100 µs after a fault condition, restoring within 0.1 seconds. Environmental limits include operating temperature -35°C to +85°C and storage temperature -51°C to +100°C. The transmitter weight is 0.43 kg (0.9 lbm).
Installation & Setup Guidance
Mount the Bently Nevada 991-06-70-03-CN on a DIN rail using the supplied DIN clips and screws (mounting option 03). Ensure the probe and extension cable are properly connected; the transmitter accepts one non-contacting 3300 NSv probe. Power supply must be +12 to +35 Vdc at the transmitter terminal. Wire the 4-20 mA output in a 2-wire configuration. For optimal performance, verify the full-scale option -06 (0.6-0-0.6 mm) matches your measurement range. The system length option -70 corresponds to a 7.0 meter (23.0 feet) cable length. Always follow standard safety practices for industrial environments.
Maintenance & Reliability
Routine inspection of the Bently Nevada 991-06-70-03-CN should include checking loop resistance and verifying the 4-20 mA output against a known reference. The environmental limits (-35°C to +85°C operating) allow installation in harsh conditions, but ensure storage temperatures stay within -51°C to +100°C. The robust DIN rail mounting and sealed enclosure minimize vibration fatigue. Periodic zero and span verification using the non-interacting external adjustments maintains accuracy. The Not OK/signal defeat function provides fast fault detection, reducing downtime by automatically signaling issues.
Troubleshooting & Common Issues
Common issues with the Bently Nevada 991-06-70-03-CN include loop faults due to high resistance or power supply problems. If the output is erratic, check that the supply voltage is between +12 and +35 Vdc at the transmitter terminal. A loop resistance exceeding 1,000 Ω can cause errors; measure resistance with a multimeter. If the output stays at less than 3.6 mA, the Not OK condition may be active – verify probe proximity and cable integrity. Zero drift can be corrected using the external adjustments. For linear range issues, ensure the probe gap is within the 0.25 to 1.65 mm linear range.
Selection Guide & Purchasing Advice
Before purchasing a Bently Nevada 991-06-70-03-CN, confirm that the full-scale option (-06, 0.6-0-0.6 mm) and system length (-70, 7.0 meters) match your application requirements. The mounting option 03 includes DIN clips and screws. The CN agency approval option ensures compliance with country-specific regulations. For reliable sourcing, visit PLC Source PRO (formerly ubest101.myshopify.com) for genuine Bently Nevada parts. Verify your existing 3300 NSv probe compatibility and power supply specifications.