Bently Nevada 3500 Series Modules – 3500/04 Earthing I/O Module - 3500/04 136719-01 128275-01F

Technical Dossier

Product Details And Specifications

Bently Nevada 3500 Series Technical Notes

The Evolution of 3500 Series Architecture

The 3500 platform was introduced in the mid-1990s as the successor to the Bently Nevada 3300 and 7200 series, consolidating discrete single-channel monitors into a unified rack system with a shared communication backplane. The original architecture used a proprietary Transient Data Interface (TDI) for waveform capture and communicated via RS-232/RS-422 serial links to host DCS systems.

The first major revision introduced the 3500/92 Communication Gateway with Modbus RTU and TCP/IP support, enabling integration with Honeywell DeltaV, Emerson Ovation, ABB 800xA, and Yokogawa CENTUM VP. A subsequent hardware revision added the 3500/93 Communication Gateway with OPC DA/UA server capability, eliminating the need for third-party OPC bridges in most installations.

The current generation introduced System 1 Evolution software compatibility, replacing the legacy System 1 v5.x platform. Modules manufactured after approximately 2010 carry the -01 or -02 firmware suffix and are not backward-compatible with pre-2005 rack firmware without a rack controller upgrade. Facilities operating original 3500 racks from the late 1990s must verify the 3500/05 Rack Interface Module (RIM) firmware version before mixing module generations. The 3500 Series is now in a mature/sustained phase; Baker Hughes continues to manufacture select modules but has issued end-of-active-development notices for several I/O variants. Long-term maintenance support and spare inventory management are therefore critical operational requirements for any facility running this platform.

3500 Series Full Catalog & Functionalities (SKU List)

Rack Infrastructure & Power

• 3500/05: Rack Interface Module (RIM) — primary rack controller and Keyphasor input processor
• 3500/04: Earthing I/O Module — rack grounding and field wiring I/O terminal interface
• 3500/15: Power Supply Module — 115/230 VAC or 24/125 VDC input, redundant-capable
• 3500/20: Rack Configuration Module — stores rack configuration data in non-volatile EEPROM

Vibration Monitoring — Proximity Probes (Eddy Current)

• 3500/40M: Proximitor/Seismic Monitor — 4-channel radial vibration and axial position monitor
• 3500/42M: Proximitor/Seismic Monitor — 4-channel enhanced version with expanded OK relay logic
• 3500/44M: Thrust Position Monitor — dual-channel axial position with configurable gap voltage range
• 3500/45: Position Monitor — 2-channel differential expansion and case expansion monitor
• 3500/46M: Hydro Monitor — 4-channel monitor optimized for low-speed hydro turbine shaft vibration

Vibration Monitoring — Seismic / Velocity

• 3500/42: Proximitor/Seismic Monitor — accepts velocity transducer (velomitor) inputs, 4-channel
• 3500/50M: Tachometer Module — single-channel speed measurement with overspeed detection to API 670
• 3500/53: Overspeed Detection System — triple-redundant speed voting logic, SIL-2 rated

Process & Temperature Monitoring

• 3500/60: Temperature Monitor — 6-channel thermocouple/RTD input, configurable per channel
• 3500/61: Temperature Monitor — 6-channel enhanced version with HART pass-through capability
• 3500/62: Process Variable Monitor — 4-channel 4-20 mA analog input for lube oil pressure and flow

Communication & Integration

• 3500/92: Communication Gateway — Modbus RTU/TCP, RS-232/RS-485, Ethernet 10/100BASE-T
• 3500/93: Communication Gateway — OPC DA/UA server, dual Ethernet, redundant-capable
• 3500/22M: Transient Data Interface (TDI) — full waveform capture, System 1 software connectivity

Sourcing Hard-to-Find & Obsolete 3500 Series Parts

Several 3500 Series modules — including early revisions of the 3500/40, 3500/42 (non-M suffix), 3500/05 (pre-2005 firmware), and 3500/20 — have been discontinued by Baker Hughes with no direct OEM replacement. Facilities that cannot migrate to the System 1 Evolution platform or the newer 3701 Series require a reliable source of tested surplus and refurbished modules to sustain existing rack installations through their remaining operational life, which in many cases extends 15 to 25 years beyond the module production end date.

Quality Control for the 3500 Series Range

The 3500 Series backplane uses a proprietary differential serial bus for inter-module communication. Functional verification of any 3500 module therefore requires a complete rack environment — isolated bench testing of individual modules without a live rack and RIM is insufficient to confirm communication integrity or relay output behavior.

DriveKNMS performs 3500 Series module verification using a dedicated test rack equipped with a calibrated 3500/05 RIM, reference 3500/15 Power Supply, and calibrated signal sources traceable to NIST standards. Each module undergoes: (1) power-on self-test (POST) pass verification; (2) channel-by-channel input simulation using calibrated proximity probe simulators or thermocouple/RTD decade boxes; (3) alarm and relay output actuation at configured setpoints; (4) communication bus integrity check via System 1 software polling; and (5) visual inspection of backplane connector pins and conformal coating condition. Modules that fail any stage are quarantined and not offered for sale.