Configured for high-speed rotational frequency measurement in the 3500 Machinery Protection System, the Bently Nevada 133388-02 (3500/50 Tachometer Module) provides direct physical signal processing for primary machine speed tracking and trip logic execution.

Model Matrix

• Part Number: 133388-02

• Functional Series: 3500/50

• Base Logic: Tachometer Monitoring

Hardware Specifications

Mechanical Monitoring and Signal Integration

The 3500/50 module requires accurate eddy-current probe scaling to define the input signal threshold for speed measurement. Each channel must undergo gap voltage validation, targeting the standard -10 VDC operational point to ensure the signal remains within the linear range of the probe. Proper configuration of the rotor dynamics threshold is necessary to prevent false speed readings during transient start-up or shut-down states. The internal circuit design incorporates cross-talk suppression to maintain input signal integrity across adjacent high-density monitoring channels within the backplane assembly.

Ordering Information

• 3500/50 Tachometer Module (133388-02)

• I/O module matching the required terminal interface (Internal/External termination)

• Standard system documentation package

Field Installation Procedures

• Backplane Seating: Ensure the module is fully seated into the 3500 rack slot to ensure proper contact with the P1/P2 backplane connectors.

• Terminal Termination: Verify whether the I/O block is configured for internal or external termination based on existing field wiring requirements.

• Signal Shielding: Use dedicated twisted-pair shielded cables for probe inputs; terminate shields at the rack safety ground point to mitigate common-mode noise.

• Hot-Swap Protocol: The module supports live insertion and extraction; verify that the Rack Interface Module (RIM) acknowledges the new module status upon power-up.

Frequently Asked Questions

• Does the module perform its own logic processing?

  Yes, the module processes raw transducer inputs locally and compares them against programmed alarm setpoints defined in the rack configuration.

• What is the maximum input frequency capacity?

  Frequency capacity is dependent on the specific transducer type and configuration settings within the 3500 software; consult the system manual for range limits.

• Can this module be used in a redundant configuration?

  Yes, the 3500 system architecture supports dual-redundant configurations for 2oo2 voting logic to minimize single-point failure risks.

• How is the 4-20 mA output scaled?

  The output is mapped to a defined RPM range within the 3500 software, allowing for linear scaling from the measured speed to the current loop.

• Does it require external loop power for the 4-20 mA output?

  The module can be configured to source loop power or act as a passive transmitter depending on the I/O module selection.

• What happens if the transducer gap voltage drifts?

  The module will report a transducer fault if the input signal exceeds the calibrated voltage range, triggering a "Not OK" status bit.

• Is the 133388-02 compatible with all 3500 rack generations?

  It is compatible with standard 3500/01 and 3500/02 rack series; verify backplane firmware compatibility during installation.

• How is firmware updated?

  Firmware updates are conducted via the Rack Interface Module (RIM) using the 3500 configuration software connection to the workstation.