Bently Nevada 3500/22-IS Transient Data Interface – Gateway and Event Capture for 3500 Machinery Protection Racks

The Bently Nevada 3500/22-IS is typically specified as a Transient Data Interface (TDI) module for the 3500 rack, combining rack interface and Ethernet communications in one slot. It acts as the data gateway to condition monitoring software, while coordinating static and dynamic waveform collection from the installed monitors. From my experience, this is the piece that quietly keeps your 3500 rack connected, synchronized, and ready to capture meaningful events during startups, coastdowns, or alarms.

• Combined rack interface + communications: Replaces the legacy RIM and provides a single, reliable gateway to host systems, reducing slot count and wiring complexity.

• Event-triggered transient capture: Acquires pre/post alarm waveforms, speed-related events (with Keyphasor inputs in the rack), and startup/coastdown data for deeper diagnostics.

• Ethernet host connection: 10/100Base‑T to condition monitoring and configuration tools, enabling high-integrity collection of static values and dynamic waveforms.

• Front-panel status at a glance: You might notice the clear OK and TX/RX indicators that make basic troubleshooting faster on the plant floor.

• Rack OK relay (via I/O): Provides a summarized health contact for DCS/ESD handshaking—useful for permissives and simple alarming.

• Time coordination: Supports time synchronization over the network in many cases, helping align waveform data with plant events.

• -IS designation: Typically requested for projects with hazardous-area compliance requirements; final approval depends on the complete rack build and site classification.

• Field-upgradable firmware: Keeps your rack aligned with the latest System 1 connectivity and capture performance improvements.

This module sits at the heart of machinery protection racks across oil & gas, petrochemical, power generation, pulp & paper, and mining. You’ll usually see it tied to high-criticality assets—steam and gas turbines, compressors, centrifugal pumps, and large motors—where transient waveform capture during trips or process upsets really matters.

• Turbomachinery trains requiring API 670‑style protection and condition monitoring

• Compressor stations and pipeline assets needing consistent event data for root cause analysis

• Refinery and petrochemical units where alarms must be correlated with process historians

• Balance-of-plant equipment fleets where centralized monitoring reduces site callouts

• Reliability that plant teams trust: The TDI seems to be one of those “install and forget” modules—once commissioned, it just keeps feeding data.

• Seamless host integration: Direct Ethernet connection to condition monitoring software reduces gateways and one-off drivers.

• Lower lifecycle cost: Fewer modules to maintain than separate RIM + comms hardware, and firmware can be updated during planned outages.

• Procurement confidence: Broad installed base, strong parts availability, and stable firmware releases typically shorten project risk.

• Hazardous area projects: When specified as 3500/22-IS, it’s usually matched with a rack build targeting ATEX/IECEx compliance; we still recommend verifying final approvals against your option code list.

• Panel/Cabinet: Mount the 3500 main rack in a 19-inch enclosure with good airflow. Keep clearances around the rack and avoid mounting near high-heat sources.

• Wiring: Use shielded Ethernet where EMC is a concern and bond the rack ground properly. Route sensor cables away from power lines; maintain bend radius and labeling for all I/O.

• Networking: Segment the monitoring network if possible. Assign a fixed IP to the 3500/22-IS and document it in your maintenance records. Enable time sync (NTP) for consistent event timestamps.

• Safety: For hazardous areas, confirm the rack’s full option codes and certificates match the site zone/class/division. IS field wiring typically requires approved barriers/isolators.

• Routine care: Periodically check front-panel LEDs and the rack OK relay function. Back up the rack configuration after any change. Schedule firmware updates during outages and verify connectivity to the host after each update.

• Health checks: In many cases, a quick ping test and a short trend review in the host software will flag issues early—simple but effective.

• CE and UL/cUL typically applicable for 3500 series modules

• ATEX/IECEx options may apply to -IS builds when used within certified rack configurations

• Manufactured under ISO-based quality systems (device-level marking varies by option code)

• Standard manufacturer’s warranty; extended coverage often available through service agreements

• 3500/05 System Rack (main rack for module installation)

• 3500/22 I/O Module (paired rear I/O providing rack OK relay and Ethernet port)

• 3500/25 Keyphasor Module (enables speed/phase information for transient capture)

• 3500/92 Communications Gateway (for Modbus/OPC connectivity when required by DCS/PLC)

• Appropriate IS barriers/isolators when field wiring is in hazardous areas

Quick customer note: One maintenance lead told me they swapped a legacy RIM/serial setup for a 3500/22-based Ethernet link and cut their transient upload time by half. Not dramatic on paper, but it made their root-cause reviews happen the same shift, not the next day.