I/O Module 138708-01 BENTLY NEVADA 3500/42M

 

138708-01 is the Shaft Absolute I/O Module designed for use with the Bently Nevada 3500/42M Proximitor/Seismic Monitor in the Bently Nevada 3500 Machinery Protection System. Featuring an Internal Termination configuration, the module interfaces with Proximitor proximity probes, Velomitor® velocity sensors, and Seismoprobe® sensors to receive and transmit shaft absolute vibration, bearing vibration, and other machinery condition signals.

Installed at the rear of the 3500 Rack, the 138708-01 operates together with the corresponding 3500/42M Monitor to provide accurate signal transmission between field sensors and the monitoring system. It is widely used for continuous condition monitoring and machinery protection of critical rotating equipment, including steam turbines, gas turbines, compressors, generators, pumps, and other industrial rotating machinery.

We can offer 138708-01 brand-new, in-stock, and discontinued spare parts. Before shipment, we will conduct model verification, appearance inspection, and packaging confirmation. We also provide product pictures, nameplate information, and compatibility confirmation services to help users complete equipment maintenance, system upgrades, and spare parts inventory management, thereby reducing installation risks and procurement cycles caused by model mismatches.

138708-01 itself does not undertake vibration analysis, alarm judgment, or data communication. Instead, it functions as an important interface module between the on-site sensors and the 3500/42M Monitor. It is responsible for transmitting measurement signals from Proximitor proximity probes, Velomitor speed sensors, or Seismoprobe seismic sensors to the monitoring module, which then performs signal processing, alarm output, and communication functions through the 3500/42M.

Compared with conventional vibration measurement methods, Shaft Absolute Monitoring not only combines the shaft's relative displacement with the bearing housing's vibration data but also conducts a comprehensive analysis of the actual movement state of the rotating shaft. It can more accurately reflect the operating conditions of large rotating equipment, and thus is widely used in mechanical protection systems that comply with the API 670 standard.

138708-01 adopts a modular design and can be directly installed in the standard 3500 Rack. No additional interface conversion board is required to complete the system connection. For users who already have a 3500 system, during equipment maintenance, system upgrade, or spare part replacement, they can quickly replace the equipment according to the original system configuration, maintaining the consistency of the on-site wiring method and system structure.

 Meet the application requirements of Shaft Absolute Monitoring

Absolute vibration monitoring of shafts is a commonly used monitoring method for large steam turbines, gas turbines, and compressors.
Compared with simply measuring the relative displacement of the shaft, Shaft Absolute Monitoring can comprehensively reflect the actual vibration situation of the rotating shaft relative to the foundation. Therefore, it is widely used in critical rotating equipment.
138708-01 is precisely designed for this measurement method, and it can meet the configuration requirements for absolute vibration monitoring of shafts in the 3500/42M system.

 Used in conjunction with the 3500/42M Monitor

138708-01 is designed in conjunction with the 3500/42M Monitor.
Among them:

138708-01 Responsibility:
On-site sensor connection
Signal input
Internal termination

3500/42M Monitor is responsible for:
Signal processing
Vibration analysis
Alarm output
Communication function

 Working Principle

138708-01 In the 3500 Machinery Protection System, it mainly undertakes the function of connecting on-site sensor signals. Its working process is as follows:

Proximitor Probe / Velomitor Sensor / Seismoprobe

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138708-01 Shaft Absolute I/O Module

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3500/42M Proximitor/Seismic Monitor

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3500 Rack Backplane

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3500/22M TDI Module

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DCS / PLC / SCADA / Condition Monitoring Software

When the on-site sensors detect changes in the equipment's vibration, the measurement signals first enter the 138708-01 module. After the module completes the signal connection, it transmits the data to the 3500/42M Monitor for processing. The Monitor, based on the system configuration, performs signal calculation, alarm judgment, and mechanical protection logic, and sends the information through the internal bus of the 3500 rack to the TDI module to achieve data communication with the DCS, PLC, or condition monitoring software.