Product Overview
When unplanned downtime hits your rotating machinery, the Bently Nevada 991-06-50-02-CN delivers fast fault detection. This Probe Vibration Transmitter is designed for axial thrust monitoring in critical turbomachinery. Its 4-20 mA output and rapid Not OK signal defeat (less than 3.6 mA within 100 µs) ensure operators receive immediate alerts, minimizing damage and repair costs.
Part of the 991 series, the 991-06-50-02-CN accepts one non-contacting 3300 NSv proximity probe and extension cable. The transmitter operates over a wide temperature range (-35°C to +85°C) and stores safely from -51°C to +100°C. With a weight of only 0.43 kg (0.9 lbm), it mounts easily on a DIN rail.
Technical Specifications Breakdown
Key parameters of the Bently Nevada 991-06-50-02-CN are derived directly from the product datasheet. These specs ensure reliable performance in harsh industrial environments.
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Output Signal: 4-20 mA over specified full-scale range in 2-wire configuration.
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Loop Accuracy: Within ±1.5% of full scale (typical) when measured across a 250 Ω loop resistance from TEST signal input.
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Maximum Loop Resistance: 1,000 Ω including cable at 35 Vdc.
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Current Limiting: 23 mA typical.
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Power Requirement: +12 to +35 Vdc input at the transmitter terminal.
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Linear Range: 0.25 to 1.65 mm for Prox Out; supports 0.6-0-0.6 mm or 25-0-25 mils current loop linear ranges.
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Zero and Span: Non-interacting external adjustments.
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Not OK/Signal Defeat: Output drops below 3.6 mA within 100 µs upon fault; restores within 0.1 seconds when fault clears.
Installation & Setup Guidance
The 991-06-50-02-CN mounts on a standard DIN rail. Accepts one non-contacting 3300 NSv proximity probe with extension cable. Power requires +12 to +35 Vdc at the transmitter terminal. Use loop resistance up to 1,000 Ω at 35 Vdc. Adjust zero and span externally without interaction. For axial thrust measurements, align the probe per manufacturer guidelines.
Maintenance & Reliability
With an operating temperature range of -35°C to +85°C, the Bently Nevada 991-06-50-02-CN withstands extreme conditions. Storage from -51°C to +100°C adds flexibility. The rapid Not OK signal defeat protects downstream equipment. Regular inspection of probe and cable integrity is recommended. No scheduled calibration required beyond typical loop checks.
Troubleshooting & Common Issues
Common problems with thrust transmitters include probe damage, cable breakage, or power supply fluctuations. The 991-06-50-02-CN’s current limiting (23 mA typical) prevents overcurrent. If output stays at <3.6 mA, check for a Not OK condition (fault within 100 µs). If loop resistance exceeds 1,000 Ω, reduce cable length or increase supply voltage. The non-interacting zero/span adjustments simplify field recalibration.
Selection Guide & Purchasing Advice
When ordering the Bently Nevada 991-06-50-02-CN, verify the full-scale option (-06: 0.6-0-0.6 mm) and system length (-50: 5.0 meters / 16.4 feet). The mounting option (02: bulkhead screws) and agency approval (CN: country specific) are included. For reliable supply, purchase from ubest101 (the store behind PLC Source PRO) to ensure genuine parts and prompt delivery.