- Automation & ControlView all 1,607 products
- AC Drives
- Industrial Communications
- PLC & I/O Cards
- Vibration Monitoring
- Automation Accessories
- Controllers & Data Acquisition
- CCTV & Security
- Safety Switches & Guard Locking
- Encoders
- Industrial Computers
- Servo Drives
- Motor Soft Starters
- HMI Displays
- Pneumatic Cylinders
- Isolator & Barrier
- Automation Software
- Machine Vision
- Robotics
Brand: Bently Nevada
Bently Nevada 135489-02 3500 I/O, 2 Prox/Accel + 2 Velomitor
Description
Bently Nevada 135489-02 3500 I/O module with internal barriers, 2 x Prox/Accel and 2 x Velomitor channels
The Bently Nevada 135489-02 is a rear I/O module for the 3500/42M that carries intrinsic-safety barriers inside the rack module and uses internal terminations. In the 3500/42M ordering code it is I/O option 05. The configuration is two Prox/Accel channels (1 and 2) and two Velomitor channels (3 and 4), which means the module can feed hazardous-area transducer circuits without a separate set of barriers in the field cabinet.
Seven Star LLC supplies the module in Oman and the GCC for plants that protect equipment in hazardous areas or want to simplify cabinet wiring. The datasheet for the barrier I/O family is a separate manufacturer document (141495); the 3500/42M datasheet is attached.
135489-02 technical specifications
| Parameter | Specification |
|---|---|
| Manufacturer / part number | Bently Nevada 135489-02 |
| Description | 3500 I/O module with internal barriers, internal terminations, two Prox/Accel channels (1 and 2) and two Velomitor channels (3 and 4) |
| Ordering option (3500/42M) | AA = 05 |
| Compatible monitor | 3500/42M Proximitor Seismic Monitor |
| Rack position | 1 full-height rear slot, behind the 3500/42M main module |
| Dimensions, non-barrier I/O | 241.3 x 24.4 x 99.1 mm (9.50 x 0.96 x 3.90 in), 0.20 kg (0.44 lb) |
| Operating temperature | -30°C to +65°C; 0°C to +65°C for internal-barrier I/O with internal terminations |
| Storage temperature | -40°C to +85°C |
| Humidity | 95%, non-condensing |
| Barrier circuit (Proximitor barrier) | Vmax PWR 26.80 V / SIG 14.05 V; Imax PWR 112.8 mA / SIG 2.82 mA |
| Hazardous area (with 3500/42M) | Class I Zone 2 AEx/Ex nA nC ic [ia Ga] IIC T4 Gc, Class I Div 2 with IS output for Division 1; ATEX II 3(1) G, at Ta -20°C to +65°C per drawing 138547 |
Barrier values are those printed in the 3500/42M datasheet for the monitor with internal-barrier I/O.
What internal barriers change
A barrier limits voltage and current going into a hazardous area so that a transducer circuit cannot ignite a gas atmosphere. In a standard 3500 rack that job is done by separate barrier hardware; here it is built into the I/O module. The trade-off is temperature: the datasheet limits operation to 0°C to +65°C for the internal-barrier I/O with internal terminations, so a rack that sees sub-zero conditions is not suitable. Barrier modules must also be installed per the drawings cited in the approvals.
Grounding is part of the safety concept. Follow the earthing instructions for the barrier drawing and never bypass the signal common termination.
Channel layout for 135489-02
The module splits its channels: Proximitor or accelerometer sensors on channels 1 and 2 and Velomitor sensors on channels 3 and 4. That layout matches a bearing with two shaft probes and two casing sensors.
| Part number | Channel configuration |
|---|---|
| 135489-02 | Prox/Accel on channels 1 and 2, Velomitor on channels 3 and 4 |
Compatible modules and alternatives
The front module is a 3500/42M (176449-02, 140734-02). Sister modules in the same barrier series are 135489-01 (four Prox/Accel channels), 135489-02 (two Prox/Accel plus two Velomitor) and 135489-03 (four Velomitor). The 3500/40M uses a similar barrier module numbered 135489-04. Non-barrier alternatives for safe-area work are 128229-01 and 128240-01.
Selection and ordering checklist for 135489-02
- Check that the Velomitor sensors really are on channels 3 and 4 and the probes on channels 1 and 2.
- Confirm the temperature floor of 0°C is acceptable at the rack location.
- Check the hazardous-area drawing required by the plant authority.
- Verify that internal terminations (not external blocks) match the field wiring.
- State the quantity of connector headers needed as spares.
Installation and maintenance
Handle barrier modules as safety equipment: use the installation drawing, do not modify the module, and record the serial number in the safety file. Fit the module before the monitor, torque the connector screws, and verify transducer supply voltage and gap on every channel at commissioning. Replace as a complete module if a barrier fault is suspected, and never repair fuses or barrier components in the field.
Use in Oman and the GCC
Hazardous-area machinery protection is common on offshore platforms, gas processing, refineries and petrochemical complexes in the region. Barrier I/O modules help there because they reduce external hardware and allow transducers in classified zones to be wired straight to the rack.
Why the 135489-02 split layout is useful
The 135489-02 puts Proximitor or accelerometer inputs on channels 1 and 2 and Velomitor inputs on channels 3 and 4. A bearing with an X-Y probe pair and a casing-mounted Velomitor pair is the classic use: the first monitor pair measures shaft radial vibration, the second measures casing velocity, and both can be configured in the same 3500/42M. The fixed split means the channels cannot be exchanged in the field, so label the front panel and the junction box clearly.
If your machine needs Velomitors on all four channels use 135489-03; if it needs Prox/Accel on all four use 135489-01. A wrong module will still fit the rack slot but the supply parameters will not match the sensors.
Information to send with your RFQ
- Part number 135489-02 and quantity
- Monitor and I/O module currently installed
- Area classification and drawing reference
- Delivery location in Oman or the GCC
Related Bently Nevada products: Bently Nevada 3500/62 Process Variable Monitor, Bently Nevada 125680-01 3500/40M Proximitor I/O Module, Bently Nevada 135489-04 3500/40M Proximitor Internal Barrier I/O, Bently Nevada 128240-01 3500/42M Prox/Seismic I/O Module, Bently Nevada 3500/70M Recip Impulse Velocity Monitor and Bently Nevada 3500/46M Hydro Monitor.
Documents and quotation
The manufacturer datasheet for the 3500/42M monitor and its I/O modules is attached on this page; read it together with your rack configuration and the site specification before confirming an order.
Seven Star LLC is an independent supplier in Muscat serving Oman and the GCC. Stock position, lead time, condition and the certificates that travel with the shipment are confirmed in the written quotation.
Other Models in the 3500 42m Io Barrier Range
Seven Star LLC supplies models from the 3500 42m Io Barrier range in Oman and the GCC. Compare the related models below and request a quote for the one that matches your application.
| Model | Category | |
|---|---|---|
| Bently Nevada 135489-01 3500 I/O Module, 4 Prox/Accel | Vibration Monitoring | View details |
| Bently Nevada 135489-02 3500 I/O, 2 Prox/Accel + 2 Velomitor | Vibration Monitoring | You are viewing this model |
Datasheets & Documents
- Datasheet Bently Nevada 3500/42M Datasheet Download
Reviews (0)
About brand
Bently Nevada is the American machinery protection and condition monitoring brand behind the 3500 rack, the 3300 XL proximity probe and the System 1 software. It was founded in 1961 in Minden, Nevada, and is today a Baker Hughes business.
Seven Star LLC is an independent supplier in Muscat. We list Bently Nevada monitors, I/O modules, probes, proximitors, velocity transducers and transmitters for rotating equipment in Oman and the GCC, and source them by full part number.
Bently Nevada company profile
| Established | 1961, Minden, Nevada, USA, by Donald E. Bently. The business started earlier as Bently Scientific in Berkeley, California (1956). |
|---|---|
| Known for | The first commercial eddy-current proximity transducers for measuring shaft vibration and position on high-speed turbomachinery |
| Ownership | Acquired by GE Energy in 2002; part of Baker Hughes since GE Oil & Gas combined with Baker Hughes in 2017 |
| Rack generations | 5000 series (from 1965), 3300 series (from 1988), 3500 series (from 1995), Orbit 60 (current platform) |
| Product families | Machinery protection racks, proximity probes and proximitors, Keyphasor sensors, velocity and acceleration transducers, 2-wire vibration transmitters, general-purpose monitors, portable analyzers, wireless sensors and System 1 condition monitoring software |
| Typical machines | Steam and gas turbines, centrifugal and reciprocating compressors, pumps, motors, generators, fans and gearboxes |
Milestones
- 1956: Donald E. Bently starts Bently Scientific in Berkeley, California.
- 1961: The company moves to Minden, Nevada, as Bently Nevada.
- 1965: The 5000 series monitoring system is introduced.
- 1988: The 3300 series follows.
- 1995: The 3500 machinery protection system is launched.
- 2002 and 2017: GE Energy acquires Bently Nevada; it becomes part of Baker Hughes in 2017.
Bently Nevada product series
| Series | Type | What it does |
|---|---|---|
| 3500 | Machinery protection rack | Continuous online protection with alarm and danger relays. Modules include the 3500/15 power supply, 3500/20 rack interface, 3500/25 Keyphasor, 3500/42M proximitor/seismic, 3500/50 tachometer, 3500/60 temperature, 3500/33 relay and 3500/92 communication gateway |
| 3500 recip modules | Reciprocating compressor monitoring | 3500/70M impulse velocity, 3500/72M rod position and 3500/77M cylinder pressure |
| Orbit 60 | Protection and monitoring platform | The current Bently Nevada platform for protection, condition monitoring and data integration with System 1 |
| 3300 XL 8 mm | Proximity transducer system | Probe, extension cable and proximitor sensor for radial vibration, thrust position and Keyphasor reference on fluid-film bearing machines; also 5 mm and 25 mm versions |
| 330500 Velomitor, 190501 Velomitor CT | Piezo-velocity sensors | Casing velocity on rolling-element bearing machines and low-speed cooling tower fans |
| 990 and 991 | 2-wire transmitters | 4-20 mA vibration (990) and thrust position (991) signals straight into a PLC or DCS, without a monitor rack |
| 1900/65A, 2300 | Compact monitors | Protection for balance-of-plant pumps, fans and motors where a full 3500 rack is not justified |
A proximity probe measures the gap to the shaft, so it sees shaft movement inside a fluid-film bearing directly. A velocity or acceleration sensor sits on the casing and suits rolling-element bearing machines. Critical turbomachinery usually carries two X-Y probes per bearing, two axial probes for thrust position and a Keyphasor probe for speed and phase.
Where Bently Nevada systems are used
In Oman and the GCC, Bently Nevada racks and probes protect gas turbines, compressors and steam turbines in gas processing, LNG, refining, petrochemical, power and desalination plants. Many installations are 3500 racks that have run for years, so most requests are for like-for-like module, probe, extension cable and proximitor replacements, plus upgrades to newer monitors.
Ordering and replacement: what we need
For probes and proximitors, send the full part number with all option digits (for example 330101-00-27-10-02-05). The digits set the probe length, cable length, connector and approvals, and the probe, cable and proximitor must match in total system length. For 3500 modules, send the module and I/O part numbers from the rack and say whether the I/O is internal or external termination, or barrier type. If a module is obsolete, we quote the replacement that Bently Nevada names and point out any configuration or firmware change.
Facts checked against Baker Hughes Bently Nevada pages and published company history, October 2026.
Browse Bently Nevada products by category: Vibration.
Related products
Frequently Asked Questions
What is the 135489-02?
It is a 3500 rear I/O module with internal barriers and internal terminations, with two Prox/Accel and two Velomitor channels.
Which monitor does it work with?
It is a rear I/O module for the 3500/42M Proximitor Seismic Monitor, installed in the full-height rear slot behind the monitor.
Does it need an external termination block?
No. It uses internal terminations, so external termination blocks cannot be fitted with it.
What temperature range applies to barrier I/O modules?
The datasheet gives 0°C to +65°C for the internal barrier I/O with internal terminations, against -30°C to +65°C for the other I/O modules.
What documents help with selection?
The 3500/42M datasheet lists all I/O modules with their ordering options, supply parameters and spares. The internal barrier datasheet 141495 applies to barrier modules.
Reviews
There are no reviews yet.