Product Core Brief
- Model: MTL5517
- Brand: MTL (Eaton Crouse-Hinds)
- Series: MTL5500 Series Intrinsic Safety Isolators
- Core Function: Provides galvanic isolation and signal conditioning for digital inputs from switches and proximity detectors in hazardous areas.
- Product Type: 2-Channel Digital Input Isolator / Safety Barrier
- Key Specs: 2 Channels | Line Fault Detection | Phase Reversal Protection | DIN Rail Mount
- Condition: New Original (New Surplus)
Product Introduction
The is a high-reliability, 2-channel digital input isolator from the MTL5500 series, designed for interfacing field devices in hazardous areas with control systems in safe areas. It serves as the critical safety barrier for discrete signals from mechanical switches, NAMUR proximity detectors, and solid-state sensors, ensuring that potentially explosive atmospheres are never exposed to unsafe energy levels.
Engineered for operational simplicity and safety, the features user-selectable line fault detection (LFD) and phase reversal protection for each channel via side-mounted switches. Its compact DIN rail mounting, quick-release mechanism, and plug-in terminal blocks facilitate fast installation and maintenance, making it an ideal choice for process control applications in oil & gas, chemical, and pharmaceutical industries.
MTL 4544AS
Key Technical Specifications
| Parameter | Value |
|---|---|
| Module Type | 2-Channel Digital Input Isolator |
| Signal Type | Switch / Proximity Detector (NAMUR) |
| Channel Count | 2 Independent Channels |
| Power Supply | 20-35 Vdc |
| Line Fault Detection (LFD) | User-Selectable per Channel |
| Phase Reversal | Independent, User-Selectable per Channel |
| Switching Frequency | DC to 500 Hz |
| Galvanic Isolation | 250V rms (Safe Area to Power) |
| Mounting | 35mm T-section DIN Rail |
| Certifications | IECEx, ATEX, Zone 0 |
Quality Control Process (Engineer’s Perspective)
We don’t just box these and ship them. Here is our actual bench test workflow.
- Incoming Verification: We verify the serial number against MTL/Eaton traceability records. A visual inspection checks for physical damage, ensures the DIN rail clip is intact, and verifies the side-mounted configuration switches are set to factory defaults.
- Live Functional Test: We mount the unit in a live test rack. We simulate switch closures and NAMUR signals on both channels and verify the relay outputs and status LEDs update correctly.
- Electrical Parameter Test: We perform a 500 V Megger test between the field input terminals and the safe-area output terminals. Insulation resistance must exceed 10 MΩ. Ground continuity is verified.
- Diagnostic Injection Test: We intentionally inject open-circuit and short-circuit faults to confirm the user-selectable Line Fault Detection (LFD) triggers the correct red LED indicator without affecting the other channel.
- Final QC & Packaging: The module is sealed in an anti-static bag with silica gel. A QC sticker showing the test date and technician initials is applied to the exterior.
MTL 4544AS
Replacement Pitfall Guide
Field replacements on safety barriers are unforgiving. Watch out for these traps.
- Configuration Switch Mismatch: ❗ Critical. The has user-selectable switches for Line Fault Detection and Phase Reversal on each channel. If you pull the old card and forget to transfer these switch settings to the new one, the system may report false faults or fail to detect real wire breaks.
- Signal Type Confusion: ❗ Critical. Verify your field device is compatible. The is designed for switches and NAMUR proximity detectors. Connecting a standard 4-20mA transmitter to this module will not work and could damage the device.
- Terminal / Cable Incompatibility: Inspect the field wiring before connecting. A shorted switch or grounded cable will trigger the LFD circuit, mimicking a module failure. Ensure terminal screws are torqued to spec to prevent intermittent connections.
- Power Supply Voltage: Verify your safe-area power supply is within the 20-35 Vdc range. Voltage outside this window can cause erratic operation or prevent the module from functioning.
- ESD Damage: Safety barriers are sensitive to electrostatic discharge. Always wear a grounded wrist strap when handling the bare PCB. I’ve seen modules fail bench testing because they were handled on a dry winter day without protection.
Keep these in mind and you’ll cut 90% of rework time.
Compatibility Matrix & Benchmarks
Compatibility
- MTL MTL5017 → : Direct Replacement – MTL5017 is the discontinued predecessor; is the direct, plug-in compatible successor with enhanced features.
- MTL Rev A → Rev B : Direct Replacement – Verify configuration switch settings match the application.
Benchmarks
- Switching Response: < 1 ms (from field signal change to output state change)
- LFD Response: < 100 ms (from fault injection to red LED assertion)
Need the wiring diagram for the digital inputs? I can pull up the termination schematic showing the 2-wire NAMUR and 3-wire switch configurations, along with the side-switch settings for LFD and phase reversal.
