Bently Nevada 21000-00-00-00-042-03-02 Retrofit-Ready Proximity Probe for 3300 XL Control Systems
The Bently Nevada 21000-00-00-00-042-03-02 is a high-precision eddy-current proximity probe assembly engineered for seamless integration into existing 3300 XL Series vibration monitoring systems. Designed to meet the demanding requirements of industrial rotating machinery protection, this probe is a verified drop-in replacement for aging or discontinued 3300 Series proximity probe assemblies. Whether you are modernizing a legacy turbine protection panel, upgrading a compressor monitoring rack, or restoring a critical vibration loop after probe failure, the 21000-00-00-00-042-03-02 delivers the dimensional accuracy, signal linearity, and gap voltage characteristics required for uninterrupted system continuity.
Industrial facilities operating Bently Nevada 3300 XL monitors — including the 3300/16 and 3300/55 series rack-mounted monitors — frequently encounter probe obsolescence as part of broader control system lifecycle management. The 21000-00-00-00-042-03-02 is purpose-built to address this challenge, offering full backward compatibility with the 3300 XL signal conditioning chain without requiring firmware changes, monitor recalibration, or rewiring of existing junction boxes. Its 5-metre integral cable and standard TNC connector interface directly with the 3300 XL proximitor/seismic transducer, maintaining the original 200 mV/mil (7.87 V/mm) sensitivity specification that your existing alarm and trip setpoints depend on.
Upgrade Compatibility Table
| Parameter | Detail |
|---|---|
| SKU / Part Number | 21000-00-00-00-042-03-02 |
| Compatible Monitor Series | Bently Nevada 3300 XL (3300/16, 3300/55, 3300/25) |
| Replaces / Supersedes | 3300 XL proximity probe assemblies (discontinued variants) |
| Probe Tip Diameter | 8 mm (standard) |
| Cable Length | 5 m integral armoured cable |
| Connector Interface | TNC (compatible with 3300 XL proximitor input) |
| Sensitivity | 200 mV/mil (7.87 V/mm) |
| Linear Range | 0.25 mm – 2.25 mm (10 – 90 mil) |
| Supply Voltage | –24 VDC (via proximitor/driver) |
| Installation Requirement | Standard M10 probe holder; no bracket modification required |
| Communication Compatibility | Analogue 4–20 mA / voltage output via 3300 XL monitor |
| Retrofit Complexity | Low — direct swap, no re-ranging required |
| Commissioning Checkpoint | Gap voltage verification at –10.0 VDC ±0.5 V nominal |
| Warranty | 12 months from date of shipment |
Retrofit Planning for Existing Automation Systems
A successful retrofit of the 21000-00-00-00-042-03-02 into an operating plant begins well before the maintenance window opens. Engineers should first audit the existing 3300 XL rack configuration, confirming which monitor slots are occupied by radial vibration, axial position, or speed channels. In a typical turbine protection cabinet, the 3300 XL rack may house a combination of 3300/16 dual-channel vibration monitors, a 3300/55 keyphasor module, and a 3300/25 temperature monitor — all sharing a common backplane power bus fed by a dedicated –24 VDC power supply module. Verifying that the power supply has sufficient current headroom to support the replacement probe and its associated proximitor driver is a mandatory pre-installation step.
Terminal wiring for the 21000-00-00-00-042-03-02 follows the standard Bently Nevada three-wire convention: shield, centre conductor, and outer conductor routed through the field junction box to the proximitor input terminals on the monitor front panel. Before disconnecting the old probe, technicians should photograph or document the existing terminal assignments, particularly if the junction box also carries signals from a 3500/42M proximitor or a legacy 7200 Series probe that may share conduit runs. Confirming that the new probe’s cable jacket and armour are rated for the ambient temperature and chemical environment of the installation zone — especially in petrochemical or offshore applications — prevents premature insulation degradation.
For facilities migrating from older 3300 non-XL monitors to the 3300 XL platform as part of a broader control system upgrade, the 21000-00-00-00-042-03-02 eliminates the need to re-specify probe geometry or re-machine probe holders. The probe is dimensionally identical to the original 3300 Series specification, meaning existing stainless-steel probe holders, lock nuts, and extension cables remain serviceable. If the retrofit also involves replacing the proximitor driver — for example, substituting a 3300 XL 8mm proximitor for a discontinued 3300 driver — the gap voltage and sensitivity curves remain consistent, preserving the alarm and trip thresholds already validated in the DCS or safety instrumented system (SIS) logic.
Where the control system upgrade extends beyond vibration monitoring to include I/O expansion — such as adding Bently Nevada 3500 Series rack modules for online machinery management — the 21000-00-00-00-042-03-02 can serve as the field sensor feeding both the legacy 3300 XL monitor and a new 3500/42M four-channel monitor via a signal splitter, enabling parallel operation during the transition period. This approach is particularly valuable when the plant’s DCS — whether a Honeywell Experion, Emerson DeltaV, or ABB 800xA system — requires continuous vibration data throughout the cutover to avoid spurious trip signals reaching the emergency shutdown system (ESD).
Downtime Control During System Migration
Minimising unplanned downtime during a proximity probe replacement is a primary concern for rotating equipment engineers. The 21000-00-00-00-042-03-02 is pre-tested and gap-verified prior to shipment, reducing on-site commissioning time to a single gap voltage check and a functional loop test against the 3300 XL monitor’s OK relay output. For critical machinery — steam turbines, centrifugal compressors, or boiler feed pumps — the recommended procedure is to perform the probe swap during a scheduled outage window, with the replacement probe pre-staged and gap-set on a bench fixture before the machine is taken offline.
To protect existing program logic and HMI displays during the migration, engineers should confirm that the 3300 XL monitor’s channel configuration — including full-scale range, alarm setpoints, and OK limits — is documented and backed up before any hardware is disturbed. If the plant uses a Bently Nevada System 1 condition monitoring platform or a third-party SCADA system to trend vibration data, the historian tag assignments and engineering unit scaling should be verified against the replacement probe’s sensitivity specification before the new probe is energised. This prevents false alarms or missed trips during the initial hours of post-maintenance operation, when the machinery is most vulnerable to transient vibration events.
For facilities that cannot tolerate any interruption to vibration monitoring — such as continuous process plants operating under API 670 requirements — a hot-swap strategy using a temporary bypass relay on the 3300 XL OK output can maintain the protection logic in a permissive state during the brief probe disconnection interval. This approach requires coordination with the plant’s safety management system and should be documented in the management of change (MOC) record. Once the 21000-00-00-00-042-03-02 is installed and gap-verified, the bypass is removed and the monitor is returned to normal protective service, typically within 15–30 minutes of the physical swap.
Retrofit Support FAQ
Q1: Is the 21000-00-00-00-042-03-02 a direct replacement for all 3300 XL proximity probe variants?
A: The 21000-00-00-00-042-03-02 is a direct dimensional and electrical replacement for standard 8 mm, 5-metre cable 3300 XL proximity probe assemblies. For non-standard cable lengths or probe tip diameters, please confirm the original part number before ordering. Our technical team can cross-reference your existing probe specification against available replacement options.
Q2: What commissioning checks are required after installation?
A: After physical installation, verify the gap voltage at the proximitor output terminal — nominal is –10.0 VDC ±0.5 V with the probe tip positioned at the centre of the linear range (approximately 1.0–1.5 mm from the target). Confirm the 3300 XL monitor’s OK LED is illuminated and that the channel is reading within the expected vibration baseline for the machine at rest. A functional test of the alarm and trip relay outputs is recommended before returning the machine to service.
Q3: Can this probe be used with a Bently Nevada 3500 Series monitor?
A: The 21000-00-00-00-042-03-02 is optimised for the 3300 XL signal conditioning chain. While the probe’s physical and electrical characteristics are compatible with the 3500 Series proximitor input, full system validation against the 3500/42M monitor’s OK and not-OK thresholds is recommended. Contact our technical support team for application-specific guidance if you are migrating from a 3300 XL to a 3500 Series platform.
Q4: What does the 12-month warranty cover?
A: All units are shipped after functional testing and gap verification. The 12-month warranty covers manufacturing defects in materials and workmanship under normal operating conditions. It does not cover damage resulting from incorrect installation, mechanical impact, or operation outside the specified supply voltage and temperature range. Warranty claims are supported by our technical team with a target response time of one business day.
© 2026 SMARTNEXMSK. All rights reserved.
Original Source: https://smartnexmsk.com
Contact: sales@smartnexmsk.com | +86 18259474341
