Bently 18745-03 Proximitor Sensor for 7200‑XL Series

Description

Hardware & Electrical Specifications

‑ Manufacturer: Bently Nevada (Baker Hughes) ‑ Device Type: 7200‑XL Eddy‑current Proximitor Sensor ‑ Compatible Probes: 5 mm, 8 mm eddy‑current proximity probes ‑ Power Supply: ‑24 Vdc ±1 V, maximum current consumption 30 mA ‑ Analog Output 1: 4‑20 mA, maximum load 750 Ω ‑ Analog Output 2: ±10 Vdc, minimum load 5 kΩ ‑ BNC Buffered Output Sensitivity: 7.87 V/mm (200 mV/mil), tolerance ±5 % ‑ Linear Accuracy: ≤ ±0.5 % full‑scale range ‑ Frequency Response: 0‑10 kHz (‑3dB) ‑ Operating Temperature: ‑30 ℃ ~ +85 ℃ ‑ Storage Temperature: ‑40 ℃ ~ +100 ℃ ‑ Mounting: DIN‑rail clip mounting ‑ Housing Material: Blue flame‑retardant engineering plastic ‑ Certifications: CE, UL, CSA Class I Div2, ATEX Zone 2 hazardous‑area approvals

Environmental Specifications

‑ Relative Humidity: 5%‑95 %, non‑condensing ‑ Vibration Resistance: Suitable for typical industrial cabinet vibration conditions ‑ EMI Immunity: Built‑in radio‑frequency interference suppression against variable‑frequency drives and power‑cable crosstalk

Core Functions

1. Eddy‑current signal conditioning: Processes high‑frequency RF signals from probe‑extension‑cable assembly, converts physical gap changes between probe and target into standard industrial analog signals.
2. Dual analog outputs: 4‑20 mA current output for long‑distance transmission to DCS/PLC; ±10 V voltage output for local instrument interfaces.
3. BNC buffered test port: Delivers raw vibration waveform for on‑site waveform observation and troubleshooting with oscilloscope.
4. Probe loop self‑diagnosis: Continuously detects open‑circuit and short‑circuit faults of probe and extension cable, and provides loop‑fault status for system alarming.
5. Non‑contact measurement: No mechanical wear, designed for long‑term online monitoring of high‑speed rotating shafts on turbines and compressors.

Installation, Replacement & Critical Warnings

1. This is an active signal‑conditioning device, not hot‑swappable. Disconnect the ‑24 Vdc power supply before any wiring operation.
2. The total calibrated system cable length (probe plus extension cable) must match the proximitor specification. Random replacement of extension cables with different lengths is prohibited.
3. 5 mm and 8 mm probe types must match this proximitor; cross‑model mixing is not allowed.
4. Mount on DIN‑rail inside cabinet, keep sufficient separation from high‑power contactors and variable‑frequency drives. Route signal cables separately from power cables.
5. Tighten terminal screws to proper torque to avoid poor connections. Cap the unused BNC test port for protection.
6. Power negative and signal ground shall follow single‑point‑grounding requirements per drawing to prevent ground‑loop noise.

Commissioning and Verification Criteria

1. Confirm ‑24 Vdc power supply stays within tolerance range and wiring polarity is correct.
2. Static gap calibration: Move probe target across working range, verify 4‑20 mA and ±10 V outputs follow gap variation with good linearity.
3. Observe raw waveform via BNC port; waveform shall be clean without abnormal noise or glitches.
4. Simulate probe open‑circuit and short‑circuit conditions to confirm loop‑fault alarm triggers properly.
5. Under machine operating conditions, vibration and displacement readings remain stable without jumping or drifting.

Common Failure Modes and Symptoms

‑ Power supply abnormality: No output and faulty loop status; inspect ‑24 V power and wiring connections. ‑ Probe / extension‑cable open or short circuit: Proximitor reports loop fault, analog output saturates or holds fixed value. ‑ Mismatched total cable length: Degraded linear performance and overall reading offset. ‑ Ground‑loop interference: Waveform superimposed with power‑frequency noise and irregular reading fluctuation. ‑ Damaged BNC connector: Raw waveform observation fails, while 4‑20 mA and voltage outputs may still function normally.

Typical Application Scenarios

Widely deployed in thermal‑power plants, coal‑chemical and combined‑cycle facilities for online shaft‑vibration and thrust‑position monitoring of steam turbines, gas turbines, centrifugal compressors and generators. Output signals connect to DCS, PLC or Bently 3300 monitoring systems for equipment condition monitoring and fault diagnosis, complying with API‑670 machinery‑protection specifications.