3500/50M Tachometer Module – Functional Overview

The 3500/50M Tachometer Module is a two-channel speed monitoring module designed to accept input signals from proximity probes or magnetic pickups. It accurately measures shaft rotational speed, rotor acceleration, and rotor direction.
These measured values are continuously compared against user-programmable alarm setpoints, and the module generates alarms whenever configured limits are exceeded.

The 3500/50M is configured using the 3500 Rack Configuration Software, allowing flexible adaptation to a wide range of rotating machinery applications.

Configuration Options

Each channel of the 3500/50M can be configured for one of the following monitoring and alarming functions:

Speed Monitoring with Setpoint Alarming and Speed Band Alarming

Speed Monitoring with Setpoint Alarming and Zero-Speed Notification

Speed Monitoring with Setpoint Alarming and Rotor Acceleration Alarming

Speed Monitoring with Setpoint Alarming and Reverse Rotation Notification

These options enable comprehensive speed-related protection and condition monitoring for critical machinery.

Keyphasor Signal Capability

The 3500/50M can be configured to provide conditioned Keyphasor® signals directly to the 3500 rack backplane for use by other monitoring modules.
This integrated capability eliminates the need for a separate Keyphasor module, simplifying rack configuration and reducing hardware requirements.

Peak Hold Feature

The Tachometer Module includes a peak hold function that stores:

The highest forward speed

The highest reverse speed, or

The total number of reverse rotations reached by the machine

Stored peak values can be manually reset, allowing operators and maintenance personnel to track maximum operating conditions over defined periods.

BENTLY 286566-02 Tachometer Module