This dual-channel speed monitoring module is designed for high-reliability monitoring of rotating machinery. It supports proximity probes and magnetic pickup sensors to provide accurate speed, acceleration, and direction measurements. The module integrates keyphasor functionality, flexible alarm logic, and peak value recording, making it suitable for critical protection and condition monitoring applications.

Input & Measurement Specifications

Number of channels: 2 independent channels

Input types:

Proximity probe

Magnetic pickup (MPU)

Measurement range: 0.1 RPM to 60,000 RPM

Output Signals

Conditioned key phase signal (to backplane)

4–20 mA analog output

Relay contact outputs

Monitoring Functions

Speed monitoring

Rotor acceleration monitoring

Direction of rotation (forward/reverse)

Zero speed detection

Alarm & Protection Functions

Programmable alarm setpoints

Alarm types include:

Speed band alarm

Zero speed alarm

Acceleration alarm

Reverse rotation alarm

Supports rapid response to abnormal operating conditions to minimize equipment risk and downtime

Peak Hold & Diagnostics

Peak holding of:

Maximum speed

Maximum reverse speed

Number of reversals (resettable)

Diagnostic functions support fast fault identification and root cause analysis

Key Features

Dual-channel independent monitoring:
Enables simultaneous monitoring of two shafts or redundant measurement of a single shaft, improving system availability and reliability.

Multifunction capability:
Combines speed, acceleration, and direction monitoring in a single module, suitable for a wide range of rotating machinery.

Flexible alarm configuration:
Multiple alarm modes allow precise adaptation to different operating and protection requirements.

Integrated key phase function:
Provides conditioned key phase signals directly to the 3500 frame backplane, eliminating the need for a separate keyphasor module.

BENTLY 3500/50M 286566-02 Tachometer Module

Peak value recording:
Captures extreme operating conditions for improved diagnostics and maintenance planning.

Software & Firmware Compatibility

Configuration software: 3500/01 Configuration Software V4.20 or later

Firmware: V5.30 or later

Environmental & Mechanical Specifications

Operating temperature: 0 °C to +60 °C

Weight: Approximately 1.36 kg (3.0 lbs)