Product Introduction
The Bently Nevada 991-25-70-02-05 is a precision Probe Vibration Transmitter designed for axial thrust measurement in rotating machinery. This Industrial Automation Module replaces older thrust monitoring systems with a reliable 4-20 mA output, simplifying integration into modern PLC and DCS controllers. Manufactured in the U.S.A., the 991-25-70-02-05 offers a full-scale range of 25-0-25 mils and a system length of 7.0 meters (23.0 feet) with bulkhead screw mounting.
Technical Specifications
Key performance parameters for the Bently Nevada 991-25-70-02-05 include:
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Output Signal: 4-20 mA in a two-wire configuration
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Power Requirement: +12 to +35 Vdc at the transmitter terminal
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Linear Range: 0.25 to 1.65 mm for proximity output (suitable for 0.6-0-0.6 mm or 25-0-25 mils current loop)
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Accuracy: ±1.5% over specified full scale (typical)
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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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Operating Temperature: -35°C to +85°C (-31°F to +185°F)
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Storage Temperature: -51°C to +100°C (-60°F to +212°F)
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Weight: 0.43 kg (0.9 lbm)
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Mounting: DIN rail compatible
The 991-25-70-02-05 also features non-interacting zero and span adjustments, and a Not OK/Signal Defeat function that forces the output below 3.6 mA within 100 µs when a fault is detected.
Installation & Setup
Mount the Bently Nevada 991-25-70-02-05 on a standard DIN rail. Connect one non-contacting 3300 NSv proximity probe and extension cable to the input. Wire the two-wire 4-20 mA loop with a supply voltage between +12 and +35 Vdc. Ensure the bulkhead screws (option 02) are properly tightened. Calibrate the zero and span using the external adjustments. The system length of 7.0 meters covers most machine train distances.
Maintenance & Reliability
Reliable axial thrust monitoring reduces unplanned downtime. The 991-25-70-02-05 operates over a wide temperature range (-35°C to +85°C) and includes agency approvals for hazardous locations: CSA Division 2, ATEX Zone 0, ATEX Zone 2, and ABS maritime. Periodic inspection of the probe and cable integrity is recommended. The current limiting feature (23 mA typical) protects the loop during transient events.
Compatibility & Integration
This Industrial Automation Module integrates seamlessly with any system accepting 4-20 mA inputs. It replaces older thrust transmitters or mechanical probes by providing a linear current loop representation of axial position. Compatible with control systems from Allen-Bradley, Siemens, ABB, and others. The Not OK/Signal Defeat function ensures fail-safe operation.
Selection Guide
When ordering the Bently Nevada 991-25-70-02-05, verify your probe and cable requirements. This variant includes the -25 full-scale option (25-0-25 mils) and -70 system length (7.0 meters). For assistance, contact ubest101 (your trusted PLC Source PRO distributor) to confirm stock and agency approvals.