MTL​ (Measurement Technology Ltd) is a global leader in industrial instrumentation and hazardous area protection solutions. Specializing in intrinsic safety barriers, signal conditioners, and surge protection devices, MTL serves oil & gas, chemical, and process industries worldwide. With over 50 years of expertise, the brand delivers reliable, certified products for critical safety applications, ensuring operational excellence in explosive environments.

Product Overview

The ​MTL 4521​ is a loop-powered solenoid and alarm driver designed for reliable control of hazardous area devices from safe area locations. This intrinsically safe interface module enables safe operation of solenoids, alarms, and other low-power loads in explosive atmospheres, providing essential protection for industrial process control systems. With its robust design and comprehensive safety certifications, it ensures secure operation in Zone 0/Division 1 hazardous areas while maintaining simple installation and operation.

Key Features

• ​Intrinsic Safety​ - Certified for Zone 0/Division 1 hazardous areas (IIC, T4-T6)

• ​Loop-Powered Operation​ - Simple installation without external power requirements

• ​High Reliability​ - Robust construction for industrial environments

• ​Visual Status Indication​ - Yellow LED for output status monitoring

• ​Fast Response Time​ - <100ms response for critical alarm applications

• ​Wide Voltage Range​ - 20-35V DC operating voltage flexibility

• ​Compact Design​ - Space-efficient DIN rail mounting

• ​Global Certifications​ - ATEX, IECEx, FM, and CSA approvals

Technical Specifications

Electrical Characteristics

Input Specifications

• ​Supply Voltage Range​ | 20-35V DC operating voltage

• ​Current Consumption​ | Maximum 90mA at 24V DC

• ​Power Requirements​ | Loop-powered design

• ​Isolation​ | 250V AC galvanic isolation between input, output, and ground

Output Specifications

• ​Output Type​ | Intrinsically safe output for hazardous areas

• ​Voltage Range​ | 13.6V to 24V output capability

• ​Current Limitation​ | 48mA minimum current limit

• ​Load Resistance​ | Minimum 400Ω load resistance

• ​Ripple Performance​ | Excellent noise suppression characteristics

Performance Data

• ​Response Characteristics​ | Fast activation and deactivation

• ​Status Indication​ | Yellow LED indicates output activity

• ​Load Compatibility​ | Certified for intrinsically safe loads

• ​Safety Margin​ | Designed with appropriate safety factors

Safety Certifications

Explosion Protection

• ​ATEX Certification​ | Compliant with European explosion protection standards

• ​IECEx Certification​ | International explosion protection standard

• ​FM Approval​ | Factory Mutual research approval for North America

• ​CSA Certification​ | Canadian Standards Association approval

• ​Zone Classification​ | Suitable for Zone 0, IIC, T4-T6 hazardous areas

• ​Division Rating​ | Division 1, Group A hazardous locations

Safety Parameters

• ​Maximum Voltage (Uo)​​ | 25V

• ​Maximum Current (Io)​​ | 147mA

• ​Maximum Power (Po)​​ | 0.92W

• ​Maximum Input Voltage (Um)​​ | 253V RMS or DC

Mechanical Specifications

Physical Construction

• ​Housing Material​ | Industrial-grade materials

• ​Enclosure Design​ | Compact form factor for high-density installation

• ​Terminal Connections​ | Secure screw terminal design

• ​Mounting System​ | DIN rail compatible (35mm standard)

Environmental Specifications

• ​Operating Conditions​ | -20°C to +60°C ambient temperature

• ​Storage Conditions​ | -40°C to +80°C storage temperature

• ​Humidity Range​ | 5% to 95% RH (non-condensing)

• ​Vibration Resistance​ | Suitable for industrial environments

Applications

The MTL 4521 is ideal for:

• ​Process Industries​ - Solenoid valve control in hazardous areas

• ​Alarm Systems​ - Hazardous area alarm and warning devices

• ​Safety Systems​ - Emergency shutdown device activation

• ​Manufacturing​ - Machine control in explosive atmospheres

• ​Oil and Gas​ - Wellhead control and safety systems

• ​Chemical Processing​ - Reactor control and safety interfaces

• ​Pharmaceutical​ - Process control in classified areas

Installation & Operation

Mounting Requirements

• ​DIN Rail Mounting​ | Standard 35mm DIN rail installation

• ​Orientation​ | Any mounting position supported

• ​Clearance​ | Standard industrial spacing requirements

• ​Group Installation​ | Can be mounted with other MTL series devices

Electrical Connections

• ​Wiring​ | Standard industrial wiring practices

• ​Terminal Torque​ | Follow manufacturer's specifications

• ​Grounding​ | Proper grounding for safety and performance

• ​Cable Requirements​ | Use appropriate hazardous area cabling

Commissioning

• ​Status Verification​ | Yellow LED indicates proper operation

• ​Function Testing​ | Verify output activation and deactivation

• ​Safety Checks​ | Confirm proper installation and grounding

• ​Documentation​ | Maintain installation records

Why Choose MTL 4521?

• ​Proven Safety​ | Certified for most demanding hazardous areas

• ​Simple Installation​ | Loop-powered operation reduces wiring complexity

• ​Reliable Performance​ | MTL's reputation for industrial reliability

• ​Flexible Application​ | Suitable for various alarm and solenoid devices

• ​Global Compliance​ | International certifications for worldwide use

• ​Visual Feedback​ | Clear status indication for easy monitoring

• ​Technical Support​ | Backed by MTL's application expertise

Maintenance & Service

• ​Visual Inspection​ | Regular check of physical condition and LED status

• ​Functional Testing​ | Periodic verification of operation

• ​Terminal Check​ | Verify terminal tightness during maintenance

• ​Environmental Protection​ | Ensure operating within specifications

• ​Certification Validation​ | Maintain safety certification records