Bently Nevada 330101-00-67-20-02-CN Retrofit-Ready Proximity Probe for 3300 XL

Bently Nevada 330101-00-67-20-02-CN Retrofit-Ready Proximity Probe for 3300 XL Control Systems

The Bently Nevada 330101-00-67-20-02-CN is an 8mm eddy-current proximity probe engineered for the 3300 XL Series vibration monitoring platform. As legacy rotating machinery protection systems approach end-of-life or face discontinued spare-parts availability, this probe serves as a verified drop-in replacement that preserves existing wiring, conduit routing, and signal chain integrity. Whether you are executing a planned outage upgrade, responding to an unplanned probe failure, or modernizing a turbine protection loop, the 330101-00-67-20-02-CN delivers the dimensional accuracy, sensitivity, and output linearity required to maintain continuous machinery health monitoring without reprogramming the host monitor or recalibrating the entire measurement chain.

Upgrade Compatibility Table

Retrofit Planning for Existing Automation Systems

Replacing a proximity probe in an operating plant requires careful coordination across multiple subsystems. The 330101-00-67-20-02-CN integrates directly with the Bently Nevada 3300 XL Proximitor/Seismic Monitor, which conditions the raw eddy-current signal and outputs a buffered voltage to the monitor rack. Before pulling the failed or aging probe, engineers should document the existing gap voltage reading from the 3300/16 or 3300/20 monitor card front-panel display or via the System 1 condition monitoring software, so the post-installation gap can be restored to the same operating point without triggering nuisance alarms.

In turbine and compressor protection panels, the probe typically shares a control cabinet with the Bently Nevada 3300/55 Dual Voting Logic module and one or more 3300/25 Keyphasor® Monitor cards. These adjacent modules do not require replacement during a probe swap, but their OK relay states should be monitored throughout the procedure to confirm the signal chain remains healthy. If the plant is also upgrading from an older 7200 Series or 3300 Standard platform to the 3300 XL architecture, the probe replacement is an ideal time to audit the proximitor extension cable (typically 5 m or 9 m armored coaxial) for insulation degradation, connector corrosion, or impedance mismatch that could introduce measurement error after the new probe is installed.

For facilities migrating their vibration data to a modern DCS or safety instrumented system, the 3300 XL monitor’s 4–20 mA analog output can be wired directly to a Rockwell Automation 1756-IF16 ControlLogix analog input module or a Siemens ET 200SP AI module without signal conditioning changes, provided the receiving module’s input impedance is within specification. This makes the 330101-00-67-20-02-CN a practical choice for hybrid modernization projects where the vibration monitoring hardware is retained while the control and historian layers are upgraded. In such configurations, the Bently Nevada TDXnet communication gateway or a Modbus TCP interface card may also be introduced to bridge the 3300 XL rack data to the plant historian or SCADA layer, and probe replacement is a natural checkpoint to verify end-to-end data continuity before the outage window closes.

I/O expansion projects that add new measurement points to an existing 3300 XL rack should also account for power budget. Each proximitor draws approximately 25 mA from the −24 VDC backplane supply. If the rack is near its power capacity, adding measurement channels may require installing an additional 3300 XL Power Supply module or redistributing loads across two rack frames connected by a 3300 XL Rack Interconnect Cable. Confirming the power budget before the outage prevents last-minute delays and ensures the new probe channel is fully commissioned within the planned maintenance window.

Downtime Control During System Migration

Minimizing unplanned downtime during a proximity probe replacement begins with pre-staging. The 330101-00-67-20-02-CN should be bench-tested against a calibrated proximitor and gap simulator before the outage begins, confirming that the output voltage at the nominal 1.0 mm gap falls within the expected −10.4 VDC ± 0.5 VDC window. This eliminates the risk of discovering a defective replacement unit after the machine is already shut down.

During the swap, the existing probe tip gap should be measured with a feeler gauge and recorded before removal. The replacement probe is threaded into the same bracket, set to the recorded gap distance, and locked with the jam nut. The monitor’s OK LED and the System 1 dynamic data display should confirm a valid signal within seconds of power restoration. If the plant uses a Bently Nevada 3500 Series monitor in parallel for redundancy or cross-validation, the 3500 channel can remain in service throughout the 3300 XL probe swap, providing continuous protection and preserving the original program logic in the safety PLC without any ladder-logic edits or function-block modifications.

For facilities that cannot tolerate any monitoring gap, a temporary portable vibration analyzer connected to the machine’s existing accelerometer or velocity transducer can provide interim protection coverage while the eddy-current channel is offline. Once the 330101-00-67-20-02-CN is installed and the gap voltage is verified, the monitor channel is re-enabled, alarm setpoints are confirmed against the original engineering basis, and the portable analyzer is removed. Total probe replacement time for a prepared crew is typically 30–60 minutes, well within a standard planned maintenance slot.

Retrofit Support FAQ

Q1: Is the 330101-00-67-20-02-CN a direct replacement for other 330101 series variants?
Yes. The 330101 series shares a common mechanical envelope and electrical interface. Variants differ primarily in cable length and connector configuration. The -00-67-20-02-CN designation specifies a 2.0 m cable with a standard coaxial connector, compatible with all 3300 XL Proximitor inputs. If your existing installation uses a different cable length variant, an extension cable can bridge the difference without affecting measurement accuracy.

Q2: Do I need to recalibrate the 3300 XL monitor after replacing the probe?
No full recalibration is required if the replacement probe is from the same 330101 series. The monitor’s scale factor and alarm setpoints remain valid. You only need to verify and adjust the physical gap to restore the correct gap voltage (typically −12 VDC at the nominal operating gap), then confirm the OK relay is energized and the dynamic data display shows a clean signal before returning the machine to service.

Q3: What wiring checks should be performed before powering up the new probe?
Inspect the coaxial extension cable for continuity and insulation resistance (>100 MΩ at 500 VDC). Verify the center conductor and shield are not shorted at either end. Confirm the proximitor connector is fully seated and the locking ring is tightened. Check that the −24 VDC supply to the proximitor is within ±1 VDC of nominal before applying power to the new probe.

Q4: What does the 12-month warranty cover?
All units shipped by SMARTNEXMSK carry a 12-month warranty from the date of shipment, covering manufacturing defects, premature electrical failure, and dimensional non-conformance. Each unit undergoes pre-shipment functional testing including gap-voltage linearity verification and insulation resistance measurement. Warranty claims are supported by our technical team at sales@smartnexmsk.com. Units damaged by incorrect installation, overvoltage, or mechanical impact are not covered under the standard warranty terms.

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