MTL 4641 DI Isolator | 1-Channel, 24V DC, Passive, IS, DIN Rail, ATEX/IECEx Specs

MTL 4641 DI Isolator | 1-Channel, 24V DC, Passive, IS, DIN Rail, ATEX/IECEx Specs

MTL 4641 DI isolator specifications. Single-channel, 24V DC input, passive, relay output, intrinsic safety barrier. ATEX/IECEx certified for Zone 1 hazardous areas.

Product Overview

The MTL 4641​ is a single-channel digital input (DI) isolator and safety barrier​ from MTL's 4600 series, designed to provide intrinsic safety, galvanic isolation, and signal conversion​ for 24V DC digital input signals​ from a hazardous-area field switch​ to a safe-area control system (PLC/DCS). This passive device provides 1500V AC isolation, converts a hazardous-area voltage input to a solid-state relay output, and carries ATEX and IECEx approvals​ for Zone 1 hazardous area installations. The 4641 protects control systems from hazardous area faults.

Technical Specifications

Note: Specifications are based on MTL 4600 series documentation. The 4641 is a passive, loop-powered device. Always verify with the latest product datasheet.

Key Features

• Intrinsic Safety:​ Approved for Zone 0/1 hazardous locations

• Galvanic Isolation:​ 1500V AC isolation protects the control system

• Passive Operation:​ Powered by the field switch loop; no separate power supply needed

• Configurable Output:​ Can be wired as a sourcing or sinking output to match the PLC/DCS input card

• Compact Design:​ Only 12.5mm wide for high-density installations

• Fast Response:​ <5 ms switching time for real-time control

• Wide Input Voltage:​ Operates with 17-30V DC field signals

• High Output Current:​ 50 mA drive suitable for most PLC digital inputs

• SIL 2 Capable:​ Suitable for safety instrumented systems

• Global Approvals:​ Certified for international hazardous area applications

Electrical Characteristics

Entity Parameters (for Hazardous Area Design)

Note: The 4641 is an associated apparatus. The field switch and wiring in the hazardous area must be intrinsically safe. The entity parameters of the connected switch must be considered.

Wiring Configuration Examples

Configuration 1: Sourcing Output (PNP) to Sinking PLC Input

[Hazardous Area]         [Safe Area]
+24V Field --- Switch --- MTL4641 Input
                          |
[Safe Area]              |
PLC COM --- PLC DI --- MTL4641 Output --- +24V Supply

Configuration 2: Sinking Output (NPN) to Sourcing PLC Input

[Hazardous Area]         [Safe Area]
+24V Field --- Switch --- MTL4641 Input
                          |
[Safe Area]              |
+24V Supply --- PLC DI --- MTL4641 Output --- PLC COM

LED Status Indicator

Typical Applications

• Hazardous Area Limit Switches:​ Position detection in Zone 1 areas

• Emergency Stop Circuits:​ E-Stop buttons in hazardous locations

• Level Switches:​ High/low level detection in tanks

• Pressure Switches:​ Alarm or shutdown signals

• Valve Position Feedback:​ Limit switches on actuated valves

• Door/Guard Interlocks:​ Safety switches on access doors

• Motor Run Feedback:​ Contactors with auxiliary contacts

• Any dry contact or solid-state switch​ in a hazardous area sending a 24V DC signal to a safe-area PLC

Important Technical Notes

1. Field Power Supply:​ The 4641 is powered by the 24V DC field signal. The field supply must be 17-30V DC and capable of supplying ~5mA.

2. Safe-side Power Supply:​ The PLC/DCS input circuit or an external 5-30V DC supply provides power for the output transistor.

3. Output Configuration:​ The output is a solid-state switch (MOSFET). It can be wired as sourcing (PNP)​ or sinking (NPN)​ to match the PLC input type. Check your PLC manual.

4. Output Current Limit:​ Maximum output current is 50 mA. Verify the PLC input current requirement is less than this.

5. Wiring Practices:​ Follow manufacturer's wiring guidelines. Maintain separation between IS and non-IS wiring. Use appropriate cable glands.

6. Certification Compliance:​ Verify that the 4641's certifications (Zone 0, IIC, T6) match your hazardous area classification.

7. Grounding:​ Proper grounding is essential for safety and noise immunity. Follow the grounding instructions in the installation manual.

8. Field Switch Type:​ Can be a dry contact (mechanical switch) or a solid-state switch (proximity sensor). The switch must be IS certified if located in the hazardous area.

9. SIL Applications:​ For SIL 2 use, follow all manufacturer guidelines for proof testing and maintenance intervals.

10. LED Indication:​ The green LED is ON when the field input is active (switch closed, 24V present). It flashes slowly when the input is inactive.

Note: This data sheet provides general specifications for the MTL 4641 digital input isolator/barrier. For complete installation guidelines, wiring diagrams, SIL documentation, and safety instructions, consult the official MTL 4600 Series Technical Manual. Always verify that the product configuration and certifications match your specific application requirements, and ensure correct wiring for your PLC input type (sourcing vs. sinking).