3500/42M Proximitor Seismic Monitor is a four-channel machinery condition monitoring module under the 3500 Machinery Protection System and serves as a critical component of the 3500 series monitoring systems. Designed for the protection and monitoring of industrial rotating machinery, it accepts signals from various types of transducers such as proximity (eddy current sensors) and seismic (vibration sensors). It enables real-time monitoring and analysis of key parameters including mechanical vibration, displacement, and acceleration. By comparing these values against user-configured alarm setpoints, it triggers timely alerts, effectively preventing mechanical failures and ensuring safe and stable equipment operation.
The 3500/42M consists of a fixed front card and a configurable rear card. For details, please refer to the Ordering page.
Key Features
The 3500/42M monitor offers robust multi-parameter monitoring capabilities. Each channel can be flexibly configured via the 3500 Rack Configuration Software to support the following monitoring functions:
The four channels operate in pairs, allowing two different monitoring functions to be performed simultaneously. For example, channels 1 and 2 can monitor radial vibration, while channels 3 and 4 monitor thrust position or acceleration.
Each channel conditions its input signal based on configuration to generate various Static Values, such as Direct, Gap, 1X/2X amplitude and phase, and Smax amplitude. Users can set Alert points for each static value and Danger points for any two static values, enabling a multi-level alarm mechanism.
Working Principle
The core operation of the 3500/42M monitor is based on signal conditioning and alarm logic judgment. Its workflow is as follows:
Signal Input:
The module accepts analog signals from eddy current sensors, accelerometers, velocity transducers, etc., supporting multiple sensitivity configurations. For example, radial vibration commonly uses 3.94 mV/μm or 7.87 mV/μm.
Signal Conditioning:
Input signals are processed through amplification, filtering, integration, etc., and converted into engineering values (e.g., μm, mm/s, m/s²). The module incorporates various filters (e.g., high-pass, low-pass, band-pass, notch) and automatically adjusts filter parameters (Filter Tracking/Stepping) based on machine speed to ensure accuracy across different operating conditions.
Parameter Calculation:
Depending on the configured monitoring type (e.g., radial vibration, acceleration, REBAM), the module calculates corresponding static values, such as:
Alarm Judgment:
Each static value can be configured with alert delays (1–60 seconds) and danger delays (0.1–60 seconds). The module continuously compares current values with setpoints and triggers corresponding alarms if thresholds are exceeded for the specified duration.
Outputs & Communication
Front-panel status LEDs (OK, TX/RX, Bypass)
Buffered transducer outputs (one coaxial connector per channel)
4–20 mA recorder output with short-circuit protection
Communication with other modules in the 3500 rack via backplane, supporting remote monitoring and data integration
Technical Characteristics
High Accuracy: Most monitoring types offer accuracy within ±0.33% (typical) to ±1% (maximum) of full scale.
Flexible Configuration: Supports multiple sensor types; each channel pair can be independently configured.
Advanced Filtering: Includes constant Q filters, elliptic filters, Butterworth filters, etc., with automatic frequency tracking.
Multiple Output Options: Buffered transducer outputs, recorder current outputs, relay alarm outputs, etc.
Environmental Adaptability: Operating temperature range from -30°C to +65°C, suitable for harsh industrial environments.
Safety Certifications: Complies with FCC, EMC, LV Directive, RoHS, ATEX, IECEx, CSA, and other international standards for use in hazardous areas.
Applications
The 3500/42M is widely used for monitoring critical rotating machinery in the following industrial sectors:
Power plants (steam turbines, gas turbines, water pumps, fans)
Oil & gas (compressors, pumps, turboexpanders)
Chemical and process industries (reactors, centrifuges)
Marine propulsion systems
Metallurgy and mining machinery
