Bently Nevada 330104-00-04-20-02-CN 3300 XL Proximity Probe

Bently Nevada 330104-00-04-20-02-CN: Retrofit-Ready Eddy Current Proximity Probe for 3300 XL Control Systems

The Bently Nevada 330104-00-04-20-02-CN is a high-precision eddy current proximity probe engineered for the 3300 XL Series machinery protection system. As legacy rotating machinery monitoring installations reach end-of-service milestones, this probe serves as the definitive retrofit-ready replacement for discontinued or worn-out sensors in turbines, compressors, pumps, and gearboxes operating under continuous vibration monitoring requirements. Whether you are upgrading an aging 3300 Series installation to the 3300 XL platform or restoring a critical monitoring loop after probe failure, the 330104-00-04-20-02-CN delivers dimensional and electrical compatibility that minimizes engineering rework and commissioning time.

This probe features a 8 mm tip diameter, 20-inch (500 mm) integral cable, and a standard 5-meter extension cable interface, making it a direct mechanical substitute in existing probe holders and conduit runs. The output sensitivity of 200 mV/mil (7.87 V/mm) is fully compatible with the 3300 XL Proximitor® sensor, including the 330180 and 330130 series Proximitor modules, ensuring that existing gap voltage calibration tables and alarm setpoints remain valid without recalibration. The probe operates within the standard -24 VDC system supply range and is rated for continuous service in environments up to 177°C (350°F), covering the majority of hot-section turbine bearing housings encountered in retrofit projects.

Upgrade Compatibility Table

Retrofit Planning for Existing Automation Systems

Successful integration of the 330104-00-04-20-02-CN into an existing machinery protection architecture begins with a systematic review of the installed system topology. In most 3300 XL and 3500 Series installations, the proximity probe loop consists of three components: the probe itself, the extension cable (typically a 330130-045-00-00 or 330130-080-00-00 coaxial assembly), and the Proximitor sensor module (such as the 330180-X0-05 or 330180-X0-CN). When replacing only the probe, the extension cable and Proximitor can remain in service provided they pass continuity and insulation resistance checks. This selective replacement strategy is the most cost-effective approach and is strongly recommended before committing to a full loop replacement.

Terminal wiring at the 3500 rack I/O module or the local junction box follows the standard Bently Nevada color-coded coaxial scheme: the center conductor carries the -24 VDC bias and the RF signal, while the shield is grounded at the Proximitor end only. Technicians should verify that the existing field wiring has not been reversed or re-terminated with non-OEM connectors, as impedance mismatches will degrade gap voltage linearity. If the installation includes a Zener barrier or galvanic isolator for intrinsically safe area classification, confirm that the barrier’s maximum output voltage and current ratings remain compatible with the new probe’s input impedance.

For sites migrating from the older 3300 Series (non-XL) to the 3300 XL platform, the 330104-00-04-20-02-CN is the recommended probe for the upgraded Proximitor. The 3300 XL Proximitor operates at a higher carrier frequency than the original 3300 Series, so mixing old probes with new Proximitor modules is not supported. A complete probe-plus-Proximitor swap is required in these cases, and the 3500/42M monitor card should be reconfigured to accept the new channel sensitivity. The 3500 rack’s I/O module, power supply module, and communication gateway (such as the 3500/92 Ethernet module or the 3500/93 Data Manager) do not require replacement during this migration, significantly reducing the scope and cost of the upgrade.

Sites operating with a DCS integration — for example, connecting the 3500 rack to a Honeywell Experion PKS, Emerson DeltaV, or ABB 800xA system via Modbus TCP or OPC DA — should verify that the channel tag assignments and engineering unit scaling in the DCS historian remain consistent after the probe swap. In most cases, because the output sensitivity is preserved, no DCS configuration change is required. However, if the site uses a 3500/22M transient data interface or a System 1 Evolution condition monitoring platform, a channel re-learn sequence may be needed to update the baseline vibration signature after the new probe is installed and gapped.

HMI faceplate displays connected to the 3500 rack via the 3500/92 module should be reviewed to confirm that the gap voltage display (typically shown as a DC voltage between -10 V and -18 V for a properly gapped probe) reflects the new probe’s installed gap. The recommended installed gap for the 330104-00-04-20-02-CN on a standard steel target is 50 mil (1.27 mm), corresponding to a gap voltage of approximately -10.0 VDC. This value should be documented in the site’s loop calibration record and verified against the HMI’s configured normal operating range before returning the machine to service.

Downtime Control During System Migration

Minimizing unplanned downtime during a proximity probe replacement requires a structured pre-outage preparation protocol. Before the machine is taken offline, the existing gap voltage, vibration amplitude (in mils peak-to-peak), and phase reference readings should be recorded from the 3500 rack’s front-panel display or from the System 1 software trend historian. These baseline values serve as the acceptance criteria for the post-installation functional test and allow the commissioning technician to confirm that the new probe is performing identically to the unit it replaces.

The physical replacement procedure for the 330104-00-04-20-02-CN is typically completed within 30 to 60 minutes per probe location, assuming the probe holder is accessible and the extension cable connector is in good condition. The most common source of extended downtime is a seized probe holder or a corroded coaxial connector at the Proximitor input. Carrying a spare 330130-045-00-00 extension cable and a set of BNC-to-TNC adapter tools in the field kit eliminates the risk of a connector failure extending the outage window.

Once the new probe is installed and gapped, the 3500 rack’s OK relay should be verified to confirm that the channel is within the configured OK limits before the machine is restarted. If the site uses a 3500/20 rack interface module for remote monitoring, the channel status should also be confirmed at the control room DCS workstation. The entire commissioning sequence — gap verification, OK relay check, vibration baseline comparison, and DCS status confirmation — can typically be completed within 15 minutes, allowing the machine to be returned to service with full confidence in the integrity of the monitoring loop.

For sites with redundant probe installations (X-Y proximity probe pairs on each bearing), it is best practice to replace both probes simultaneously during a planned outage, even if only one probe has failed. This eliminates the risk of a second probe failure during the next operating cycle and ensures that both channels share the same calibration baseline, simplifying future trend analysis in the System 1 or DCS historian.

Retrofit Support FAQ

Q1: Is the 330104-00-04-20-02-CN a direct drop-in replacement for the original 330104-00-04-20-02 (without the CN suffix)?
A: Yes. The CN suffix designates the country-of-origin variant manufactured to the same dimensional, electrical, and performance specifications as the standard part. The probe is fully interchangeable with the non-CN variant in all 3300 XL and 3500 Series installations. No wiring changes, sensitivity recalibration, or monitor card reconfiguration are required.

Q2: What pre-shipment testing is performed, and what documentation is included?
A: Each 330104-00-04-20-02-CN undergoes a functional test covering output sensitivity (200 mV/mil ± 10%), insulation resistance (≥ 100 MΩ at 500 VDC), and connector integrity before shipment. A test report is included with each unit. The 12-month warranty covers manufacturing defects identified during installation or normal operation and is supported by our technical team at sales@smartnexmsk.com.

Q3: Can this probe be used with a Zener barrier for Zone 1 hazardous area installations?
A: The 330104-00-04-20-02-CN is compatible with approved Zener barriers and galvanic isolators rated for the Bently Nevada 3300 XL probe loop parameters. The barrier must be certified for the installation’s area classification (ATEX, IECEx, or NEC) and must not limit the probe’s bias supply below -18 VDC under worst-case load conditions. Consult the barrier manufacturer’s entity parameters and verify compatibility with the Proximitor’s input specifications before installation.

Q4: What is the lead time, and do you maintain stock for urgent replacement orders?
A: We maintain ready stock of the 330104-00-04-20-02-CN to support urgent replacement and emergency outage scenarios. Standard orders ship within 1–3 business days. For critical machine protection applications requiring same-day dispatch, contact our team directly at sales@smartnexmsk.com or +86 18259474341 to confirm availability and arrange expedited freight.

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Contact: sales@smartnexmsk.com | +86 18259474341