Bently Nevada 3500/33-02-00 with 149992-02 – 16‑Channel Relay Module for 3500 Machinery Protection Systems

The Bently Nevada 3500/33-02-00 is the 16‑Channel Relay Module many plants rely on for hard-wired alarm and trip outputs in a 3500 rack. Paired with the rear I/O module 149992-02, it consolidates multiple machine condition alarms and makes them actionable—clean, isolated dry contacts that your ESD, PLC, or DCS can trust. From my experience, it’s typically used where you want flexible voting logic, latching vs non‑latching behavior, and a fail‑safe approach (normally energized) to reduce spurious trips.

You might notice that sites choose the 3500/33 when they need a dense set of outputs in one slot, especially on critical rotating assets: turbines, compressors, generators, high‑value pumps—the equipment where downtime is both costly and attention‑worthy. The -02 option and the 149992-02 rear I/O combination seems to be one of the more common pairings in the field because it keeps wiring straightforward and configuration consistent across units.

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• Warranty: 365 days
• Lead time: 1 week if in stock; no more than one month at the latest
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Key Features

• 16 isolated relay outputs: Dense channel count for alarm, pre‑alarm, and trip segregation without adding extra modules.
• Configurable logic and voting: AND/OR and voting schemes (e.g., 2oo3) typically available to reduce nuisance trips.
• Latching or non‑latching behavior: Set per channel to match site trip philosophy and reset procedures.
• Fail‑safe design: Normally energized mode is commonly used so loss of power is detected as a safe state.
• Rack‑powered, hot‑swappable front module: Installs in a 3500 rack slot; no separate power feed needed.
• Backplane integration: Works with 3500/22M TDI for system communications (e.g., Modbus/TCP via TDI).
• Rear I/O 149992-02: Matched terminal interface for clean field wiring and straightforward channel labeling.
• Self‑diagnostics: Module health reported through the 3500 rack, helping maintenance teams pinpoint issues early.

Technical Specifications

Brand / Model	Bently Nevada 3500/33-02-00 (Front Module) + 149992-02 (Rear I/O)
Function	16‑channel relay output module for alarms/trips within a 3500 machinery protection rack
HS Code	9032.89 (typical classification for automatic regulating/controlling instruments)
Power Requirements	Powered via 3500 rack backplane (3500/15 power supply); no external power input to the module
Operating Temperature	Typically 0 to +60 °C (refer to the latest Bently Nevada datasheet for exact limits)
Signal I/O Types	16 isolated dry‑contact relay outputs; NO/NC behavior configured via software and wiring; intended for low‑level control circuits
Communication Interfaces	Through 3500 rack backplane; system communications provided by 3500/22M TDI (e.g., Modbus/TCP via TDI)
Installation Method	Front module plugs into a standard 3500 rack slot; rear I/O 149992-02 mounts on the rack back; field wiring to rear terminals
Dimensions & Weight	3500 full‑height module form factor; typical combined mass under 1 kg (module + rear I/O)

Application Fields

Commonly deployed in integrated machinery protection systems across:

• Steam and gas turbines: trip interlocks and annunciation for overspeed, vibration, and thrust position alarms.
• Compressors and expanders: logic voting from multiple probes to prevent false trips during transient conditions.
• Pumps, fans, and blowers: consolidated alarm outputs to PLC/DCS for shutdown and operator alerts.
• Refining, petrochemical, power generation: where SIL philosophies often prefer fail‑safe relay outputs and regular proof testing.

Advantages & Value

• Reliability under plant conditions: Built for continuous service; diagnostics feed through the rack so issues are spotted early.
• System compatibility: Native fit for the 3500 platform; works alongside 3500/22M, 3500/40/42 monitors without surprises.
• Wiring efficiency: 16 outputs per slot cuts panel space and simplifies marshalling compared to multiple low‑count modules.
• Procurement confidence: Stable part numbering (3500/33-02-00 + 149992-02) makes spares stocking and interchange straightforward.
• Support for plant standards: Voting logic and fail‑safe modes help align with most site trip philosophies and MOC procedures.

Installation & Maintenance

• Cabinet & environment: Install in a 3500 rack inside a clean, ventilated cabinet. Avoid condensation and excessive vibration on the rack itself.
• Wiring practices: Use properly rated conductors; keep relay outputs away from high‑noise power cables; interpose external relays/contactors for higher currents.
• Configuration: Set relay assignments, latching, and voting in the 3500 configuration software. Verify firmware compatibility with the site’s TDI.
• Safety: De‑energize affected circuits before moving field wires. Where fail‑safe is required, choose normally energized behavior and prove it during FAT/SAT.
• Routine checks: Periodic proof tests of each channel (typically during turnaround) and visual inspection of terminals; update firmware in coordination with site change control.

Quality & Certifications

• CE marked; commonly supplied with UL/cUL compliance for industrial control equipment.
• Manufactured under ISO 9001 quality systems. RoHS conformity is typical for many hardware revisions.
• Standard manufacturer warranty practices apply; we support a 365‑day warranty on supply.

Related Components You May Need

• 3500/05 System Rack (required framework)
• 3500/15 Power Supply (AC or DC variants, redundant options)
• 3500/22M Transient Data Interface (system communications, Modbus/TCP via TDI)
• 3500/32M 4‑Channel Relay Module (when lower relay density per slot is preferred)
• Appropriate terminal labels and shielded cable for relay circuits

If you’re consolidating alarms, planning a rack expansion, or simply aligning spares to your site standard, this 3500/33-02-00 with 149992-02 rear I/O is, in many cases, the cleanest drop‑in choice. One thing I appreciate is how predictable commissioning is—set the assignments, prove the logic, and it behaves exactly as configured.