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Bently Nevada 3500 System Overview
Source: | Author:kongjiang | Published time: 2026-10-15 | 35 Views | 🔊 Click to read aloud ❚❚ ▶ | Share:
The 3500 System provides continuous, online monitoring suitable for machinery protection applications, and is designed to fully meet the requirements of the American Petroleum Institute’s API 670 standard for such systems.

3500 System Overview
Description
The 3500 System provides continuous, online monitoring suitable for machinery protection applications, and is designed to fully meet the requirements of the American Petroleum Institute’s API 670 standard for such systems.  It represents our most capable and flexible system in a traditional rack-based design, andrepresents numerous features and advantages not provided in other systems.  The system’s highly modular design consists of:
• 3500/05 Instrument Rack (required)
• One or two 3500/15 Power Supplies (required)
• 3500/22M Transient Data Interface or 3500/20 Rack Interface Module (required)
• One or two 3500/25 Keyphasor® Modules (optional)
• 3500 Rack Configuration Software (required)
• One or more 3500/XX Monitor Modules (required)
• One or more 3500/32 Relay Modules or 3500/34 TMR Relay Modules (optional)
• One or more 3500/92 Communication Gateway Modules (optional)
• 3500/93, 3500/94, or 3500/95 display OR 3500 Operator Display Software running on a compatible PC (optional)
• Internal or external intrinsic safety barriers, or galvanic isolators for hazardous area installations (optional)
These are described in more detail in the following section and in the individual
datasheets for each system component.  
System Components
Rack
The full-size 3500 Rack is available in 19” EIA railmount, panel-cutout-mount, and bulkhead-mount versions.  The rack provides slots for two Power Supplies and a Rack Interface Module in the left-most rack positions that are reserved exclusively for these modules.  The remaining 14 slots in the rack can accommodate any combination of monitor, display, relay, Keyphasor module, and communications gateway modules.  
All modules plug into the rack’s backplane and consist of a main module and an associated I/O module.  The I/O module installs at the rear of the rack for panel-mount systems, and above the main module for bulkhead-mount systems.  
The rack depth is 349 mm (13.75 inches) and NEMA 4 and 4X weatherproof housings are available when required for environmental protection or when purge air is used.   A mini-rack (12” wide instead of 19”) is also available and features 7 available monitor slots instead of 14.  Like its larger counterpart, the left-most slots are reserved for the Power Supply or Supplies and Rack Interface Module.  The mini-rack may be mounted in a panel cutout or, using an optional adapter plate, on 19” EIA mounting rails.  Bulkhead mounting is not available.  
Power Supply
The 3500/15 Power Supply can be ordered for ac or dc input power, providing compatibility with voltage
sources worldwide.  Line noise filters are standard.  The 3500 Rack can operate from a single supply, or dual Power Supplies can provide redundancy for situations which cannot tolerate power interruption. Dual supplies reside in the upper and lower positions of the left-most rack slot.  Redundant Power Supplies can use with separate voltage sources.  For example, the primary (bottom) supply can be operate with 120 Vac power while the backup (upper) supply can be powered from an uninterruptible 24 Vdc source.   EachPower Supply can individually provide power to the entire rack and its modules.  When redundant supplies are used, one supply acts as primary power for the rack while the other acts as a backup, ready to instantly and automatically operate as the primary rack supply without interrupting rack functions., should the primary supply fail.   The 3500/15 Power Supply module has selfmonitoring functions that allow it to determine if all
its output voltages are within specifications.  The module annunciates this via a green “Supply OK” LED on the Power Supply’s front panel.
Rack Interface Module/Transient Data Interface
The Transient Data Interface (TDI) or the Rack Interface Module (RIM) are the 3500 Rack’s primary interfaces to the configuration, display, and condition monitoring software.  Each rack requireas one TDI or RIM, which resides in the rack slot immediately adjacent to the Power Supply slot. The TDI and RIM support a proprietary protocol used by both the 3500 Configuration Software to configure the rack and the 3500 Operator Display Software to retrieve rack data and statuses. TDI provides a direct interface with GE’s Bently Nevada  System 1® machinery management software without the need for an external communications processor.  The RIM requires an external communications processor, such as TDXnet™, TDIX, or DDIX to interface to Data Manager® condition monitoring software. The System OK relay1 is located within the TDI/RIM’s I/O module.  It is driven by NOT OK conditions within the TDI/RIM itself and within other modules in the rack.
The TDI and RIM supply “self monitoring” functions both for themselves and for the rack, in addition to
those provided by the individual monitor, relay, communications, and other modules.  While the TDI and RIM provide certain functions common to the entire rack, neither is part of the critical monitoring path and has no effect on the proper, normal operation of the overall 3500 System or its machinery protection functions.   The TDI and RIM provide 4 front-panel LEDs as follows:
System configuration is secured by means of a keylock switch on the front of the TDI/RIM and two levels of software password protection, preventing unauthorized changes to or tampering with the configuration.  Both the TDI and the RIM can be connected to a portable computer via a front-panel serial communications port for local changes to configuration.  The RIM can also be permanently connected to a configuration workstation via a rear panel serial communications port, or to a remote computer via an optional modem I/O module. The TDI provides permanent system connectivity via Ethernet ports.
The TDI/RIM provides a front-panel DIP switch that permits the user to assign a unique rack address when multiple 3500 racks are networked with one another.  The TDI/RIM provides a system reset switch on the
front panel, allowing the user to clear any latched alarms in the system as well as latched NOT OK conditions.  An I/O module provides a set of rearpanel connections as well, allowing users to remotely activate this switch.  For Triple Modular Redundant (TMR) applications, the 3500 System requires a TMR version of the TDI/RIM (refer to the TMR section of this datasheet for additional information).  
Monitors
Table 1 summarizes available monitor types in the 3500 System.  Each monitor occupies a single slot in the rack.  All monitors are microprocessor-based and offer digitally adjustable Alert and Danger setpoints for each channel1.  Users can configure alarms for latching or non-latching operation.  Status indications foreach monitor and channel are provided with bright, front-panel LEDs, allowing observation without operator interaction for easy and convenient operation. Most monitors provide independent 4 to 20 mA proportional outputs for each channel of the I/O module for connection to strip chart recorders or for older process control systems that do not support a digital interface. Where applicable, the monitor’s I/O modules provide transducers with appropriate power via shortcircuit-protected terminals.  OK detection routines within each monitor continuously check the integrity of each transducer and the associated field wiring.  
Transducer input signals are buffered and sent to front-panel coaxial connectors2.  Buffered output terminals are also available upon request on the rear of the TDI/RIM’s I/O module.
Available 3500 Series Monitor Modules
3500/40M  
• Radial Vibration
• Axial (Thrust) Position
• Eccentricity
• Differential Expansion3
3500/42M
Same as 3500/40M, with the
following additional channel
types:
  Acceleration6
  Velocity6
  Enhanced Acceleration6  
  Enhanced Velocity6  
  Circular
AcceptanceRegion7
  Shaft Absolute
3500/44M
• Special Aeroderivative Gas
Turbine Monitoring
Functions8
3500/45
• Axial (Thrust) Position  
• Differential Expansion  
• Standard Single Ramp
Differential Expansion  
• Non-Standard Single Ramp
Differential Expansion  
• Dual Ramp Differential
Expansion  
• Complementary Differential
Expansion  
• Case Expansion9  
• Valve Position
3500/46M
• Hydro Radial Vibration10
• Hydro Stator-Mounted Air
Gap  
3500/50
• Standard Tachometer  
• Rotor Acceleration
Tachometer  
• Zero-Speed Tachometer  
3500/53
• Overspeed Tachometer
3500/602,14 and 3500/612,14
• Temperature
• Differential Temperature
3500/622,14
• Process Variables15
3500/632
• Hazardous Gas Detection
3500/64
• Dynamic Pressure16  
3500/70M
• Recip Impulse / Velocity
3500/72M
• Reciprocating Compressor Rod Drop / Rod Position / Hyper compressor
3500/77M
• Reciprocating Compressor Cylinder Pressure,
including:
- Suction Pressure - Maximum Pressure - Minimum Pressure - Compression Ratio  - Peak Rod Compression - Peak Rod Tension - Degree of Rod Reversal
 Relays1
The 3500/32 Relay Module provides four double-pole, double throw (DPDT) relays that can actuate based on alarm conditions within 3500 monitor modules.  The configuration software allows the user to program various combinations of alarms, ranging from an individual channel’s ALERT or DANGER status, to highly complex Boolean expressions that combine two or more channel statuses to provide special AND or OR voting.  By adding the desired number of relay modules, the user can provide individual contacts for each channel, alarm type, and group of channels for global alarm annunciation.  
The 3500/34 TMR Relay Module works in conjunction with a special TMR Rack Interface Module and three monitor modules to provide 2-out-of-3 voting for inputs.   Relays are epoxy-sealed and installed arc suppressors are standard.  Users can program relays for either normally energized or normally de-energized operation.
The 3500 Rack also supplies a common system OK relay2 in addition to any alarm relays in the rack.  This relay is located in the TDI/RIM’s I/O module and is connected to the OK circuits of all modules in the rack. These circuits monitor the operating condition of each module.  Any fault in the module, its transducers, or associated transducer field wiring will be annunciated by the OK relay.  This relay is a singlepole, double-throw (SPDT) type and is normally energized, providing added capability of annunciation in the event of primary power loss.
Keyphasor Inputs
The 3500 System can accommodate up to four1 Keyphasor transducers per rack by installing two 3500/25 Keyphasor modules in a rack2.  Each 3500/25 is a half-height module that provides power and termination for up to two Keyphasor transducers each.  When applications require Keyphasor transducers, simply install a single 3500/25 module.  Keyphasor signals from the 3500/25 module(s) can be routed to appropriate monitor modules via the 3500’s rack backplane for use in speed, phase, tracking filter, and other measurements.
Communications Gateway
With an appropriate Communications Gateway module in the rack, installations can digitally transfer selected status and current value data to process control systems, historians, plant computers, and other relevant systems.  The Communication Gateway modules support a variety of industry-standard protocols and users can install multiple Communications Gateway modules in a rack when the system requires redundant communications or must support multiple communication protocols simultaneously.  
The modules do not interfere with the 3500 System’s normal operations or machinery protection functions, ensuring that the monitoring system integrity is always maintained, even in the unlikely event of a
Communications Gateway module failure. The Communications Gateway supports both Ethernet and serial communications media, allowing a variety of wired and wireless topologies.  Communications are bi-directional, allowing selected data to be sent to and retrieved from the 3500 System.  In addition, when
installations use Ethernet to connect the Communications Gateway to process control or other systems, multiple computers running 3500 Configuration Software and/or 3500 Operator Display Software can reside on the same network.  This eliminates the need for separate connections between the software and the RIM.
Displays
The 3500 System provides the most flexible display options ever offered by the Bently Nevada product line as summarized in Table 2.  Multiple displays can be combined as needed to meet specific requirements for local and remote indication of rack statuses, measurements, and alarms.  
3500 Display Options
3500/93 LCD  Display  
Face Mounting1 – The display installs directly over the front panel of any 3500 rack using a special hinged support. This permits access to the rack’s buffered output connectors and user-interface buttons and switches without disconnecting or disabling the display.
19-inch EIA Rack Mounting – The display is mounted on 19-inch EIA rails and located up to 100 feet away from the 3500 System2.
Panel Mounting – The display is mounted in a panel cutout located in the same cabinet or up to 100 feet away from the 3500 System2.
Independent Mounting – The display is mounted in a NEMA 4X enclosure flush against a wall or panel, and located up to 100 feet away from the 3500 System2.
3500/94 VGA Display
Panel Mounting – The display is mounted in a panel cutout located in the same cabinet or up to 25 feet away from the 3500 System3.  
19-inch EIA Rack Mounting – The display is mounted on 19-inch EIA rails and located up to 25 feet away from the 3500 System3.
Shelf Mounting – The display is mounted on a shelf or tabletop and located up to 25 feet away from the 3500 System3.
3500/95 User Interface Workstation
Panel Mounting – The display is mounted in a panel cutout located in the same cabinet or up to 4000 feet away from the 3500 System4.  
Intrinsic Safety Barriers or Galvanic Isolators
For applications where the transducers are located in a hazardous area, the 3500 System can be used with internal or external intrinsic safety barriers.  However, the 3500 option for internal safety barriers is generally preferable to external barriers because this option saves cost, requires no extra cabinet space, and needs no additional wiring.  Internal barriers improve safety because the connections are pre-wired, reducing the possibility for errors introduced by wiring additional external connections between monitors and barriers.  Internal barriers also improve quality because, unlike external barriers, they require no special monitor scale factor calibration to compensate for voltage drop across the barrier.  For additional information on 3500 internal barriers, refer to datasheet 141495-01. For those that prefer the use of galvanic isolators to address intrinsic safety requirements, preengineered external galvanic isolators and an appropriate housing are available.  For additional information on 3500 galvanic isolators, refer to datasheet 141714-01.
Applications
The 3500 System is intended for continuous, permanent monitoring of rotating and reciprocating machinery in a variety of industries. It  is specifically designed for use in auto-shutdown machinery protection applications that require extremely high reliability and availability.  Machine types addressed by the 3500 System include but are not limited to:
Industrial gas and steam turbines in power generation and mechanical drive service
Aeroderivative gas turbines in power generation
and mechanical drive service  
Hydraulic (Hydro) turbines in power generation
service
Compressors (air/process gas, radial/axial,
centrifugal/positive displacement)  
Turbo Expanders  
Electric motors and generators  
Exciters  
Gear boxes
Pumps (centrifugal and positive displacement)
Fans  
Blowers  
Reciprocating compressors
Extruders and pelletizers
In addition, GE’s Bently Nevada Custom Products
engineering, can often address special requirements
for custom configuration of an existing monitor type
or modifications to a standard monitor type. Contact
your local sales professional for further information.  
Features
Digital and Analog Communications
The 3500 System features separate, concurrent digital communication capabilities for connection to:
System 1 machinery management software using
Bently Nevada proprietary protocols via Ethernet
connections
Process control and other plant automation
systems using industry-standard protocols via
the 3500’s Communications Gateway module
Bently Nevada condition monitoring systems via
pre-engineered Data Manager ports which
interface to an appropriate external
communications processor such as TDXnet,
TDIX, or DDIX
3500 Configuration and Display software
In addition, analog (4 to 20 mA and relay) outputs are available for connection to older plant controls that cannot support digital interfaces.
Highly Flexible Display Options
Displays can range from local units mounted directly on the rack’s front panel, to remote displays using wireless communications, to completely blind monitoring systems with an as-needed HMI (Human
Machine Interface) connection for configuration and information.   Multiple displays can be connected concurrently without degrading system performance or interrupting basic machinery protection functions.
Software Configurable
Virtually every aspect of the 3500’s operation is software configurable, resulting in the most flexible Bently Nevada monitoring system ever offered and in easier spare parts management.  Unlike previous systems, a single 3500 module type can be configured for a variety of functions rather than for just a single function.  The following list represents just part of the 3500’s numerous configurable options.
Density
The 3500 System can easily fit twice as many channels into the same rack space as previous monitoring systems. This results in lower installation costs by saving valuable cabinet space and spreading common components, such as displays, communications gateways, and power supplies, across more channels for lower per-channel costs.
Internal and External Terminations
Previous monitoring systems have always incorporated field wiring connections on the back of the rack.  The 3500 System offers this conventional approach with our internal termination option.  However, the 3500 system now offers an innovative external termination option that allows field wiring to
go to external terminal blocks.  These blocks can be mounted where access is more convenient, such as on a cabinet wall, and less congested than on the back of each monitor module.  The external terminal
block then connects to the monitor’s I/O module using a single pre-engineered cable, resulting in neater, more easily serviceable installations.  
Higher Integrity / Fault Tolerance
The 3500 System is the first system offered in the Bently Nevada product line that the user can
configure with varying levels of redundancy.  This ranges from simplex modules to dual power supplies to a full TMR (Triple Modular Redundant) configuration in which monitor channels (and optionally, transducers) can be triplicated participate in a 2-out-of-3 voting scheme using special relays.  This allows the 3500 to be used in safety instrumented applications that cannot tolerate false and missed trips under any circumstances, whether from a power supply, a monitor channel, or a transducer or the result of electronic failure or human error.
Even without redundancy, the 3500 system represents the most reliable monitoring system we have ever offered.  It incorporates numerous selfmonitoring functions that can identify faults in the monitor modules and their connected transducers, annunciate and identify problems via appropriate error codes, and suppress channel operation automatically when a failure could compromise correct operation of the system. The 3500 System stores configuration in two separate locations in each module’s non-volatile memory.  This redundancy allows the module to ensure that memory has not been corrupted by comparing configuration information for agreement and flagging any anomalies. The use of redundant, non-volatile memory also allows the user to program the module ahead of time for spare parts, and ensures that, in the event a redundant power supply is not used, monitor configuration is not lost when power is interrupted and monitoring functions can resume immediately upon reapplication of rack power.
Skid Mounting
In many cases, the 3500 rack can be mounted on or near the machine skid or local control panel, keeping cable runs between the 3500 rack and the machine shorter and less costly.  Wired and wireless communications and display options permit the installation to make a single Ethernet connection between the control room and 3500 rack.  This also permits installations to distribute display and other information needed, whether to a process control system or to an engineer’s desktop computer.  The result is a machinery protection system with significantly lower installation costs than those that must be mounted in only control room environments.  Optional NEMA 4 and NEMA 4X weatherproof housings are available when installations require field mounting of the 3500 System.
Remote Accessibility
Modem, WAN, or LAN connections allow the user to remotely configure a 3500 system and even assess
the system when an instrument problem arises.  Users can implement simple changes, such as to an alarm setpoint or a filter corner, without traveling to site.  This is ideal for such installations as offshore platforms, compressor or pump stations, emergency generators, and other locations where on-site access to the instrumentation is inconvenient or impractical.  
Tamper-resistant Design
In addition to conventional 19-inch rail and panelcutout mounting options, the 3500 System introduces a new bulkhead mounting option, allowing the rack to be mounted on a wall or other location where rear access to the rack is not available.