Bently Nevada 3500/45 140072-02/140072-04 Position Monitor

Technical Specifications

Parameter	Details
Product Type	Position Monitor Module
Compatibility	Bently Nevada 3500 Series Monitoring System
Number of Channels	4 independent channels
Input Types	Eddy current proximity probes (3300 XL, 3300, 7200)
Input Signal Range	–0.8 V to –21.0 V DC
Measurement Range	0 mm to 12.7 mm (adjustable per channel)
Accuracy	±0.2 % of full scale
Resolution	16-bit (0.001 V)
Sample Rate	100 samples per second per channel
Frequency Response	0 Hz to 10 kHz (DC coupled)
Filter Options	Low-pass, high-pass, band-pass (software selectable)
Alarm Outputs	4 relay outputs (form C, configurable)
Communication Protocol	Modbus RTU, Modbus TCP/IP
Dimensions (H x W x D)	241 mm x 38 mm x 254 mm
Weight	1.2 kg
Power Supply	24 VDC nominal (18 VDC to 32 VDC)
Power Consumption	8.5 W typical
Operating Temperature	–20 °C to +65 °C
Storage Temperature	–40 °C to +85 °C
Protection Class	IP20
Certifications	CE, CSA, ATEX, ABS

Product Variants Overview

Variant	Description
3500/45 140072-02	Standard position monitor with 4 channels, configured for differential expansion
3500/45 140072-04	Position monitor with 4 channels, optimized for axial thrust and case expansion

Precision Position Measurement

The 3500/45 140072-02 and 140072-04 position monitors deliver four channels of high-accuracy position data for critical rotating machinery. These modules accept inputs from eddy current proximity probes, converting raw voltage signals into engineering units such as millimeters or mils. Each unit achieves ±0.2 % accuracy across the full measurement range, supporting applications like axial thrust monitoring, differential expansion, and valve position tracking.

Specialized Application Support

The 3500/45 140072-02 version specifically targets differential expansion measurements. This variant captures relative movement between rotating and stationary machine components. Meanwhile, the 3500/45 140072-04 suits axial thrust and case expansion monitoring. Both variants offer adjustable measurement ranges per channel, enabling precise configuration for different turbine and compressor designs.

Advanced Signal Processing

Each channel on these position monitors includes software-selectable filtering options, such as low-pass, high-pass, and band-pass settings. Users can tailor the frequency response to isolate specific mechanical phenomena, including thermal growth or sudden thrust movements. The modules sample at 100 readings per second, delivering real-time position data for both monitoring and protection. Furthermore, the units output raw gap voltage at the terminal block for easy system verification during startup.

Alarm and Safety Integration

Both variants include four form C relay outputs, independently configurable for alarm, danger, or shutdown functions. Operators can define multiple setpoints per channel, enabling staged warning and protection strategies. The modules feature a built-in OK relay that indicates the health of the card and connected proximity probes. Additionally, the units support Modbus RTU and TCP/IP protocols for seamless connection to plant DCS or SCADA systems.

Physical and Environmental Specifications

Weighing 1.2 kg and measuring 241 mm x 38 mm x 254 mm, these modules fit into standard half-height slots in the 3500 series rack. They consume 8.5 W from a nominal 24 VDC supply and operate reliably from –20 °C to +65 °C. The IP20-rated housing provides adequate protection for industrial control room installations.