Phoenix MACX MCR-EX Series: Intrinsically Safe Signal Conditioning Modules for Hazardous Areas - Comprehensive Application & Selection Guide

Product Positioning & Core Value

The Phoenix MACX MCR-EX Series represents a range of intrinsically safe (Ex) signal conditioning modules engineered exclusively for hazardous environments (ATEX/IECEx Zone 0/1/2, Class I/II/III Div 1/2). Designed to process and isolate signals from NAMUR sensors, RTD temperature detectors, and other industrial transducers, these modules ensure safe, reliable signal transmission between field devices and controllers (PLCs/DCS) in explosive gas/dust atmospheres.

Key value propositions include:

• Intrinsic Safety: Complies with ATEX/IECEx standards (II 2G Ex ia IIC T4 Ga, II 2D Ex ia IIIC T135°C Da) for Zone 0/1/2 hazardous areas.
• Signal Versatility: Supports NAMUR sensors (active/passive), RTD temperature sensors (Pt100/Pt1000), and discrete signals with multiple output configurations (relay, transistor, universal voltage).
• High Reliability: 3-way galvanic isolation (input-output-power, 2kV), SIL 2/3 compliance (per IEC 61508), and -20°C~+55°C operating temperature range.
• Industrial Durability: Flame-retardant V0 housing, IP20 protection, and resistance to electromagnetic interference (EMI) – critical for harsh process environments.

Ideal for oil & gas, chemical, pharmaceutical, and coal mining industries, the series minimizes ignition risks while ensuring precise signal conversion and conditioning for safety-critical applications.

Product Family Overview

The MACX MCR-EX Series is categorized by signal type and output function to meet specialized hazardous area requirements:

1. NAMUR Sensor Signal Conditioning Modules (SL-NAM Series)

• Function: Process signals from NAMUR-compliant sensors (active/passive proximity switches, position sensors) with intrinsic safety protection.
• Key Variants (Output Types):
  • R: Relay output (NO/NC changeover contacts).
  • NAM: Dual NAMUR signal output (for redundant systems).
  • 2T: Dual transistor output (PNP/NPN, for high-speed switching).
  • 2RO: Dual relay output (for dual-load control).
  • IDSI-I: Intrinsically safe digital input with analog output (4-20mA).
  • 2NAM-T: Dual NAMUR input + transistor output.
  • 2NAM-R-UP: Dual NAMUR input + relay output + universal voltage output (UP).
  • 2NAM-RO: Dual NAMUR input + relay output.
• Special Suffixes:
  • SP: Special protection (enhanced EMI resistance, overload protection).
  • UP: Universal output (compatible with multiple controller inputs).
• Typical Models: MACX MCR-EX-SL-NAM-R-SP, MACX MCR-EX-SL-NAM-2T, MACX MCR-EX-SL-2NAM-RO-SP.

2. RTD Temperature Signal Conditioning Modules (EX-RTD Series)

• Function: Specialized processing for RTD temperature sensors (Pt100/Pt1000) in hazardous areas, with lead wire resistance compensation and cold junction compensation.
• Key Variants:
  • I: Analog current output (4-20mA).
  • SP: Special protection (enhanced accuracy, EMI resistance).
  • C: Cold junction compensation (for high-precision temperature measurement).
• Typical Models: MACX MCR-EX-RTD-I-SP-C, MACX MCR-EX-RTD-I, MACX MCR-EX-RTD-I-SP.

Technical Specifications (Universal Parameters)

Detailed Function Module Introduction

1. NAMUR Sensor Signal Conditioning Modules (SL-NAM Series)

2. RTD Temperature Signal Conditioning Modules (EX-RTD Series)

Application Scenario Analysis

1. Oil & Gas Refineries (Zone 1/2, Class I Div 1)

Recommended Configuration:

• NAMUR Sensor Control: MACX MCR-EX-SL-NAM-R-SP (2924045) + MACX MCR-EX-SL-NAM-2RO-SP (2924061)
• Temperature Monitoring: MACX MCR-EX-RTD-I-SP-C (1052652)

Implementation Advantages:

• Intrinsic safety prevents ignition of flammable gases (methane, propane).
• Dual relay output modules enable redundant control of emergency shutdown valves.
• High-precision RTD modules ensure accurate temperature monitoring of distillation columns.

2. Chemical Processing Plants (Zone 0/1, II 2G Ex ia IIC T4)

Recommended Configuration:

• Multi-Sensor Processing: MACX MCR-EX-SL-2NAM-R-UP-SP (2924249)
• Fast-Acting Control: MACX MCR-EX-SL-NAM-2T (2865463)
• Temperature Sensing: MACX MCR-EX-RTD-I-SP (1050252)

Implementation Advantages:

• Dual NAMUR input modules reduce wiring complexity for multi-sensor arrays.
• Transistor output modules support high-speed switching of chemical dosing pumps.
• SIL 2 compliance meets safety requirements for toxic chemical handling.

3. Pharmaceutical Manufacturing (Zone 2, Class II Div 2)

Recommended Configuration:

• Temperature Control: MACX MCR-EX-RTD-I-SP-C (1052652)
• NAMUR Proximity Sensing: MACX MCR-EX-SL-NAM-R (2865434)

Implementation Advantages:

• Cold junction compensation ensures precise temperature control of sterile processes.
• Intrinsic safety eliminates ignition risks in dust-explosive environments (powdered ingredients).
• 2kV isolation prevents cross-contamination of sensitive pharmaceutical equipment.

4. Coal Mines (Zone 20/21/22, II 2D Ex ia IIIC T135°C)

Recommended Configuration:

• Ventilation System Control: MACX MCR-EX-SL-2NAM-RO (2865476)
• Temperature Monitoring: MACX MCR-EX-RTD-I (1050222)
• Digital-Analog Conversion: MACX MCR-EX-SL-IDSI-I (2865405)

Implementation Advantages:

• Dual NAMUR modules monitor air flow sensors for redundant ventilation control.
• RTD modules withstand high-temperature, dusty environments.
• IDSI modules convert NAMUR signals to analog for PLC-based pressure monitoring.

Selection Guide

Step 1: Determine Signal Type

• NAMUR Sensors: Choose SL-NAM sub-series (e.g., MACX MCR-EX-SL-NAM-R-SP for relay output).
• RTD Temperature Sensors: Select EX-RTD sub-series (e.g., MACX MCR-EX-RTD-I-SP-C for high precision).

Step 2: Select Output Configuration

Step 3: Confirm Special Features

• Hazardous Area Class: Ensure compliance with local standards (ATEX/IECEx for EU, UL 913 for US).
• Precision Requirements: Choose SP (special protection) for enhanced accuracy/EMI resistance.
• Temperature Compensation: Select C suffix for RTD modules (cold junction compensation).
• Redundancy: Opt for dual-channel models (e.g., 2NAM, 2RO) for safety-critical systems.

Step 4: Verify Environmental & Safety Requirements

• Operating Temperature: Ensure compatibility with ambient conditions (-20°C~+55°C).
• Load Capacity: Relay modules (5A) for heavy loads, transistor modules (0.5A) for light loads.
• SIL Compliance: Confirm SIL 2/3 rating for safety-critical applications (e.g., emergency shutdown).

Installation & Maintenance Guide

Installation Steps:

1. Mounting: Snap modules onto a 35mm DIN rail in an explosion-proof enclosure, ensuring ≥5mm spacing for heat dissipation.
2. Wiring: Use intrinsically safe cables (e.g., PVC/SWA) for field connections; connect input (sensor), output (controller), and power per terminal markings (0.14~2.5mm² conductors).
3. Torque: Tighten terminal screws to 0.5~0.8Nm (prevents vibration-induced loosening).
4. Grounding: Ensure proper grounding of the module and enclosure (≤4Ω ground resistance) to maximize explosion protection.
5. Configuration: Set RTD wire type (2/3/4-wire) via DIP switches (if applicable).
6. Testing: Verify LED indicators (green = power-on, yellow = signal active) post-installation; test fault conditions to confirm safety circuit activation.

Maintenance Points:

• Status Monitoring: Regularly check LED indicators (red = fault) – replace modules immediately if fault persists.
• Calibration: Calibrate RTD modules annually using a certified temperature calibrator.
• Cable Inspection: Inspect field cables for damage/corrosion (quarterly) – replace if insulation is compromised.
• Replacement: Replace modules after 10 years of service or if exposed to a major explosion/overload event.
• Environmental Control: Keep enclosure dry (relative humidity 10~90%, non-condensing) and free of dust.

MACX MCR-EX Series vs. Traditional Ex Signal Conditioning Solutions

Summary & Next Steps

The Phoenix MACX MCR-EX Series delivers safe, precise signal conditioning for hazardous area applications, combining intrinsic safety compliance, versatile signal processing, and industrial durability. Whether for NAMUR sensor control or RTD temperature monitoring, these modules ensure reliable communication between field devices and controllers while minimizing ignition risks in explosive environments.