Bently Nevada 128987-130-00-CN Retrofit-Ready Proximity Probe for 3300 XL Control Systems
The Bently Nevada 128987-130-00-CN is a 25mm eddy current proximity probe engineered for seamless integration into existing 3300 XL vibration monitoring systems. As legacy machinery monitoring infrastructure ages and OEM support for older probe configurations becomes increasingly limited, this unit provides a verified drop-in replacement path that preserves signal chain integrity, minimizes reconfiguration effort, and eliminates the need for full system overhaul. Whether you are managing a planned upgrade cycle or responding to an unplanned failure on a critical rotating machine, the 128987-130-00-CN delivers the dimensional accuracy, cable length compatibility, and sensitivity range required to restore full monitoring capability with minimal downtime.
This probe is designed for use with the Bently Nevada 3300 XL series monitor chassis, which remains widely deployed across turbomachinery, compressor trains, and pump monitoring applications in oil & gas, power generation, and petrochemical facilities. The 3300 XL platform relies on a matched probe-extension cable-proximitor system, and the 128987-130-00-CN is factory-calibrated to work within this signal chain. When retrofitting, engineers must confirm that the existing Bently Nevada 330130 or 330180 series extension cable is compatible in length and connector type, and that the proximitor module — typically a 3300 XL 8mm or 25mm proximitor — is configured for the correct gap voltage range corresponding to this probe’s output characteristics.
Before installation, the retrofit team should verify the following: power supply capacity at the I/O rack or monitor module, terminal block wiring assignments on the 3300 XL monitor card, and the physical mounting thread (M10 x 1 standard for 25mm probes). If the existing probe was installed with a different cable assembly, the full probe-cable-proximitor set should be replaced together to maintain system calibration. Partial replacement — for example, reusing an old extension cable with a new probe — can introduce gap voltage errors that trigger false alarms or mask real vibration events.
In systems where the 3300 XL monitor communicates via a Bently Nevada 3500 rack or interfaces with a DCS through a 4–20 mA output or Modbus RTU link, the probe replacement itself does not require protocol reconfiguration. However, if the retrofit is part of a broader migration from a 3300 XL rack to a 3500/22M or 3500/42M monitor module, the engineering team will need to update the System 1 configuration database, re-map channel assignments, and verify that HMI display tags in the control room reflect the new channel numbering. This is particularly important in facilities where the vibration data feeds into a safety instrumented system or a DCS historian.
Upgrade Compatibility Table
| Parameter | 128987-130-00-CN Specification | Retrofit Notes |
|---|---|---|
| Probe Diameter | 25mm eddy current | Matches standard 3300 XL 25mm probe mounting |
| Thread Size | M10 x 1 | Verify existing bracket thread before installation |
| Cable Length | Per SKU suffix (-130 = 5m integral cable) | Match with 330130 extension cable for total system length |
| Compatible Monitor | Bently Nevada 3300 XL series | Also compatible with 3500 rack via adapter configuration |
| Proximitor Required | 3300 XL 25mm proximitor | Do not mix 8mm and 25mm proximitor modules |
| Output Signal | -18 VDC nominal gap voltage | Verify gap voltage at commissioning (typically -10V to -18V range) |
| Communication | Analog (4–20 mA / voltage output via monitor) | No protocol change required for like-for-like replacement |
| Installation | Radial or axial mounting | Confirm orientation matches original probe axis |
| Warranty | 12 Months | Covers manufacturing defects; includes pre-shipment functional test |
Retrofit Planning for Existing Automation Systems
A successful retrofit of the 128987-130-00-CN into an operating plant requires a structured bill of materials review. In most 3300 XL installations, the probe works in conjunction with a 330130-00-60-05-02-00 extension cable and a 3300 XL proximitor module mounted in the monitor rack. If the rack also houses a 3300/16 or 3300/20 monitor card, the channel configuration must be reviewed to ensure the new probe’s sensitivity factor is correctly entered. Plants running Bently Nevada System 1 software should update the probe database entry to reflect the 128987-130-00-CN model number and recalibrate the alert and danger setpoints if the original probe had a different sensitivity curve.
For facilities upgrading from older 7200 series or 3000 series Bently Nevada probes, the 128987-130-00-CN represents a forward-compatible replacement that aligns with the 3300 XL platform’s signal conditioning architecture. In these cases, the retrofit scope typically includes replacing the proximitor, updating the terminal block wiring in the junction box, and verifying that the power supply module — often a 3300 XL power supply card or an external 24 VDC rail — can support the additional current draw if multiple probes are being replaced simultaneously.
Where the control system includes a Bently Nevada 3500/22M transient data interface or a 3500/42M Ethernet communications module, the probe replacement can be completed without changes to the network configuration. However, if the plant is simultaneously migrating from a 3300 XL rack to a full 3500 rack, the project team should plan for re-termination of field cables at the new rack’s terminal blocks, re-entry of machine train configuration data, and a full functional test of the vibration channel before returning the machine to service. A Bently Nevada 3500/93 power supply module and a 3500/20 rack interface module are typically part of this broader upgrade scope.
In compressor and turbine applications where the probe monitors shaft radial vibration, the retrofit team should also confirm that the gap setting — typically 1.0 to 1.5mm for a 25mm probe — is re-established after installation using a calibrated gap tool, and that the OK relay output from the monitor card is verified before the machine is started. Pre-shipment functional testing of the 128987-130-00-CN is performed at our facility, and each unit ships with a test report confirming output linearity and gap voltage response.
Downtime Control During System Migration
Minimizing unplanned downtime during a probe replacement or system migration is a primary concern for plant reliability engineers. The 128987-130-00-CN is stocked for immediate dispatch, which supports just-in-time replacement strategies for critical rotating equipment. When planning a scheduled outage, the recommended approach is to pre-stage the replacement probe, extension cable, and proximitor module before the machine is taken offline, so that the swap can be completed within a single maintenance window.
For plants that cannot tolerate extended outages, a parallel installation strategy is sometimes used: the new probe is mounted in an adjacent bracket position and the monitor channel is switched over after gap verification, without removing the original probe until the new one is confirmed operational. This approach requires an available spare channel on the 3300 XL monitor rack or a temporary portable data collector such as a Bently Nevada ADRE 408 DSPi to validate the new probe’s signal before cutover.
Original program logic in the DCS or safety system does not need to be modified for a like-for-like probe replacement. The vibration channel tag, alarm setpoints, and historian configuration remain unchanged. If the replacement is part of a broader 3300 XL to 3500 rack migration, the control system engineer should prepare a pre-tested configuration file for the new rack and schedule the database download during the outage window to avoid extending machine downtime. All units are shipped with a 12-month warranty and a pre-shipment functional test report, supporting rapid installation and return to service.
Retrofit Support FAQ
Q: Is the 128987-130-00-CN a direct drop-in replacement for other Bently Nevada 25mm probes in the 3300 XL system?
A: Yes, for most 3300 XL installations using a 25mm probe configuration, the 128987-130-00-CN is a direct replacement. You should verify the cable suffix to confirm the integral cable length matches your existing installation, and confirm that the proximitor module is the correct 25mm variant. No recalibration of the monitor card is required if the replacement probe has the same sensitivity specification as the original.
Q: What wiring checks are required before commissioning the replacement probe?
A: Before powering up the monitor channel, verify the terminal block connections at the 3300 XL monitor card for the probe positive, probe negative, and shield conductors. Confirm that the extension cable connector is fully seated at both the probe and proximitor ends. Measure the gap voltage at the monitor’s test point to confirm it falls within the -10V to -18V operating range before starting the machine.
Q: Can this probe be used in a system that is being migrated from a 3300 XL rack to a Bently Nevada 3500 rack?
A: The 128987-130-00-CN probe itself is compatible with both 3300 XL and 3500 series monitor platforms, provided the correct proximitor module is used. During a rack migration, the probe and extension cable can be retained while the proximitor and monitor card are replaced. The System 1 configuration database will need to be updated to reflect the new rack and channel assignments.
Q: What does the 12-month warranty cover, and is a test report included?
A: The 12-month warranty covers manufacturing defects in materials and workmanship from the date of shipment. Each 128987-130-00-CN unit undergoes a pre-shipment functional test verifying output linearity, gap voltage response, and connector integrity. A test report is included with each shipment. Warranty claims are processed through our sales team with a return authorization number.
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