Triconex 3381 Pulse Input Module | 6 Ch TMR Speed Sensor

• Model 3381 is a TMR Pulse Input Module for Tricon systems.
• Each module has three isolated channels for triple redundancy.
• Channels sense voltage transitions from speed sensors and convert to frequency (RPM).
• MPs vote on the data before sending to your application.

Key Features – Made for Rotating Machines

• 6 high-frequency inputs – individually configurable for magnetic speed sensors.
• Works with turbines, compressors, and other rotating equipment.
• Counts over 32,000 transitions per second. Speed range 0 to 32,000 RPM.
• Supports non-amplified and amplified magnetic sensors.
• Hot-spare ready. Mechanically keyed to prevent wrong installation.

Technical Specifications (Tree View)

• ▹ Model: 3381 Pulse Input Module
• ▹ Compatible baseplate: Model 2381 PI Baseplate
• ▹ Number of points: 6, channel-isolated, commoned ground
• ▹ Input type: Differential
• ▹ Sensor compatibility: Magnetic, active, open collector
• ▹ Maximum operating voltage: ±33 VDC
• ▹ Minimum operating voltage (differential):
  • 500 mV P-P, 2 Hz to 32,000 Hz
  • 1 V P-P, 0.5 Hz to 2 Hz
• ▹ Minimum operating voltage (single-ended):
  • 1 V P-P, 2 Hz to 32,000 Hz
  • 2 V P-P, 0.5 Hz to 2 Hz
• ▹ Speed range: 0 to 32,000 RPM
• ▹ Input frequency range: 0.5 Hz to 32 kHz
• ▹ Duty cycle: 20% to 80%, or 10 µs minimum pulse width
• ▹ Number of gear teeth: 1 to 255 (configurable)
• ▹ Resolution: 24 bits
• ▹ Absolute error:
  • ±0.01% (2,000 to 32,000 Hz)
  • ±0.1% (0.5 to 2,000 Hz)
• ▹ Measurement algorithm: Gear multiple tracking
• ▹ Minimum scan update rate: 20 ms
• ▹ Isolation ratings:
  • Functional-to-protective-earth: 500 VDC minimum
  • Functional-to-functional-earth (logic): 800 VDC minimum

How It Works – From Sensor to RPM

• Speed sensor has an inductive coil and rotating gear teeth. Teeth move past the sensor.
• Magnetic field change creates a sinusoidal signal in the sensor.
• PI Module senses voltage transitions and measures time between pulses.
• Uses mid-value selection algorithm to pick correct data for each scan.
• Converts count and time to frequency (RPM) and sends to Main Processors.

Built-in Diagnostics & Fault Handling

• Each channel has complete, ongoing diagnostics.
• Diagnostic includes precision reference test.
• If a channel fails, FAULT indicator turns on and system alarm activates.
• Fault indicator shows channel fault, not whole module failure.
• Module works correctly with single fault. May work with multiple faults.
• Design prevents one channel failure from affecting others.

Installation Guide

• Mount the Model 3381 onto Model 2381 PI Baseplate.
• Mechanical keying prevents wrong installation. Check alignment.
• Connect speed sensors to the 6 input points. Use twisted pair cables for noise reduction.
• Configure termination resistor and pull-up resistor on baseplate.
• Set number of gear teeth (1-255) in your application software.
• Power up and check PASS LED. Green means OK.

Easy Debug & Maintenance

• FAULT LED per channel – quickly find which input has issues.
• Hot-spare support – replace a faulty module without stopping the system.
• Use Tricon diagnostics to read per-channel health data.
• Signal ringing? Check sensor wiring and grounding.

Compatibility

• Works with Tricon v9.6 and later systems.
• Requires Model 2381 PI Baseplate (sold separately).
• Compatible with magnetic speed sensors (passive), active sensors, and open collector.
• Can integrate with Modicon Quantum via Tricon communication modules.

Certifications & Safety

• TÜV certified for SIL 3 safety applications per IEC 61508.
• Isolation ratings: 500 VDC (functional-to-earth), 800 VDC (logic).
• Designed for high-availability rotating machinery protection.

Package Contents & Warranty

• 12 months warranty from invoice date. Covers manufacturing defects.
• Package includes: 1 x Triconex 3381 Pulse Input Module only.
• Baseplate (Model 2381) sold separately. No cables included.
• Return defective units for replacement under warranty.

Shipping – Fast Worldwide Delivery

• We ship with FedEx, UPS, DHL express services.
• Tracking number within 24 hours. Insurance included.
• Typical delivery: 3-7 business days.

Typical Applications

• Gas and steam turbine speed monitoring.
• Compressor overspeed protection systems.
• Rotating machinery RPM measurement for safety shutdown.
• High-speed gearbox monitoring.

Diagnostic Capability

• Per-channel precision reference test – runs continuously.
• Detects open wire, sensor failure, or signal loss.
• FAULT LED pinpoints bad channel quickly.
• System alarm triggers on persistent faults.
• Ring detection helps identify signal distortion issues.

Frequently Asked Questions (FAQ)

• Question: What sensors work with Model 3381?

  Answer: Magnetic speed sensors (passive), active sensors, and open collector types.

• Question: Can I use this module without the 2381 baseplate?

  Answer: No. Model 3381 requires Model 2381 PI Baseplate for proper operation.

• Question: What does the FAULT LED mean?

  Answer: One channel has a failure. Replace the module if the fault persists.

• Question: How fast can it measure RPM changes?

  Answer: Maximum slew rate: 4,000 RPM/sec with 60 gear teeth.

• Question: Does it support hot-swap?

  Answer: Yes. Hot-spare support allows replacement without system shutdown.

Experience-based Q&A (Field Notes)

• Question: My RPM reading jumps around. What causes this?

  Answer: Check for signal ringing or noise. Use shielded cables and proper termination resistor.

• Question: One channel shows FAULT but others work fine.

  Answer: That channel likely failed. Replace the module. The system still runs safely.

• Question: Can I connect a 24V active sensor directly?

  Answer: Yes if output is open collector or ≤±33V. Check sensor specs first.

• Question: We get extra counts at low speed. Why?

  Answer: Low-frequency signal may have noise. Enable debounce filtering in configuration.

Buying Guide – Select the Right Pulse Input Module

• Choose Model 3381 if you need 6 TMR-protected speed inputs for turbines or compressors.
• Need fewer inputs? Look at other Tricon PI modules with 4 or 2 points.
• Always buy the Model 2381 Baseplate together – they are a pair.
• Check your gear teeth count (1-255). Program it correctly for accurate RPM.
• For overspeed protection systems, order two or three modules for separate voting paths.
• Contact us for bulk pricing or trade-in options for older PI modules (3380, etc.).

Need Help? Contact Our Team

• Technical support or quote requests:
  +86 158 8020 0923 (WhatsApp)
• Email: sales@plcdcshub.com – reply within 24 hours.
• Pre-sales consulting, datasheets, and RMA support available.

Copyright © 2026 PLCDCS HUB Limited. All rights reserved.
Original Source: https://plcdcshub.com/
Partner: Powergear X Automation Limited |
Oiltech Controls Limited