Product Overview

The MTL3011 is an isolated repeater with relay output. This unit enables a safe-area load to be controlled by a proximity detector or switch located in a hazardous area. The MTL3011 provides a relay output for general use in industrial control systems. A built-in phase-reverse control allows an alarm condition (output open) to be signalled for either state of the sensor. Furthermore, a line-fault detection feature opens the output in the event of short or open-circuit lines. Consequently, this device offers comprehensive protection for critical control circuits.

Technical Specifications

The MTL3011 delivers reliable switching with full galvanic isolation. Below are the core technical details.

General Specifications:

• Number of Channels: One, fully floating channel.

• Location of Switch: Zone 0, IIC, T6 hazardous area; Div. 1, Group A hazardous location.

• Location of Proximity Detector: Zone 0, IIC, T4-6 hazardous area (if suitably certified); Div. 1, Group A hazardous location.

• Weight: 140g.

Power Requirements:

• Typical Current Consumption: 25mA at 24V.

• Maximum Current Consumption: 35mA at 20 to 35V.

• Typical Power Dissipation: 0.6W at 24V.

• Maximum Power Dissipation: 1.3W at 35V.

Hazardous-Area Input Specifications

The MTL3011 accepts inputs from NAMUR-compliant devices in hazardous locations.

• Voltage Applied to Sensor: 7.7 to 9.0V DC from 1kΩ.

• Input Standard: Conforms to NAMUR and DIN 19234 standards for proximity detectors.

Input/Output Characteristics

The MTL3011 defines clear switching thresholds with hysteresis.

• Output Closed (Relay Energized): If >2.1mA (<2kΩ) in sensor circuit.

• Output Open (Relay De-energized): If <1.2mA (>10kΩ) in sensor circuit.

• Hysteresis: 200µA (650Ω) nominal.

Phase Reverse Facility

The MTL3011 includes a convenient phase reversal feature.

• Operation: Reversed by a switch located on top of the unit.

• Function: Allows an alarm condition (output open) to be signalled for either sensor state.

• Benefit: No rewiring is required to change between normally open and normally closed operation.

Line Fault Detection (LFD)

The MTL3011 provides built-in line fault detection for enhanced safety.

Detection Thresholds:

• Output Open (Broken Line): If input current <100µA.

• Output Open (Shorted Lines): If input current >6.5mA.

Important Notes:

• To prevent false triggering of LFD, switch-type sensors must be fitted with resistors.

• Alternatively, LFD can be disabled by linking terminals 7 and 8.

• This feature is intended primarily for use with proximity detectors.

• Nevertheless, it can also be used with switches made to resemble them electrically by adding two resistors.

Power Supply Failure Protection

The MTL3011 includes failsafe protection for power loss.

• Protection Action: Output circuit opens if supply fails.

• Result: The relay de-energizes, signalling a safe condition.

• Benefit: This fail-open behaviour is preferred for most safety applications.

Output Characteristics (Relay)

The MTL3011 provides a light-duty relay output for general use.

Electrical Ratings:

• Response Time: 1ms typical.

• Contact Rating: 200V, 0.5A, 10VA (AC); 200V, 0.5A, 10W (DC).

• USA Rating: 60V individual maxima (resistive loads).

• Contact Life Expectancy: 0.75 x 10⁶ operations at maximum load.

Important Note:
Reactive loads must be adequately suppressed to protect the light-duty contacts in this unit.

LED Indicator

The MTL3011 provides clear visual status indication.

• LED Function: ON when output circuit is closed (relay energized).

• Location: Front panel for easy viewing.

• Benefit: Simplifies troubleshooting and status verification.

Replaceable Fuse

The MTL3011 includes a field-replaceable fuse for protection.

• Rating: 50mA.

• Size: 5 x 20mm glass.

• Type: Semi-time-lag (M) to DIN 41571 sheet 2.

• Benefit: Easy replacement without replacing the entire unit.

Safety Description

The MTL3011 includes intrinsic safety parameters for hazardous area installation.

• Safety Parameters: 10.5V, 800Ω, 14mA.

• Um: 250V rms or DC.

FM Maximum Entity Parameters:

• Voc: 10.5V.

• Isc: 10.7mA.

• Ca: 3.0µF.

• La: 300mH.

Key Features

The MTL3011 offers several advantages for switching applications in hazardous areas.

Relay Output:

• Provides a clean, isolated contact for general use.

• Suitable for AC or DC loads up to 200V.

• Consequently, it works with most industrial control systems.

Zone 0 Certification:

• Approved for Zone 0, IIC, T6 hazardous areas for switches.

• For proximity detectors, certified for Zone 0, IIC, T4-6 (when suitably certified).

• Therefore, input devices can be placed in the most demanding hazardous zones.

NAMUR Compatibility:

• Conforms to DIN 19234 standards for proximity detectors.

• In addition, it works with dry contact switches using added resistors.

• Thus, it supports most hazardous area input devices.

Adjustable Phase Reversal:

• Operated by a simple switch on top of the unit.

• As a result, output polarity can be matched to the control system.

• No hardware changes or rewiring are required.

Line Fault Detection (LFD):

• Detects open-circuit and short-circuit conditions on field wiring.

• Furthermore, detected faults open the output relay.

• This enhances safety by preventing undetected wiring failures.

• LFD can be disabled if not required.

Power Failure Protection:

• Output circuit opens automatically if supply fails.

• Therefore, the system fails to a safe state.

• This is essential for emergency shutdown applications.

Replaceable Fuse:

• Protects the unit from overcurrent damage.

• Easy to replace without special tools.

• Reduces maintenance downtime.

Resistor Requirements for Switch Inputs with LFD Enabled

When using the MTL3011 with dry contact switches and LFD enabled, the following resistors must be fitted:

Alternative: If resistor fitting is not practical, disable LFD by linking terminals 7 and 8.

Typical Applications

The MTL3011 suits a wide range of switching applications.

• Proximity sensor interfacing in chemical processing plants.

• Limit switch monitoring in oil and gas facilities.

• Level switch signalling in pharmaceutical manufacturing.

• Pressure switch interfacing in Zone 0 locations.

• Temperature switch monitoring in hazardous environments.

Installation Guidelines

Install the MTL3011 in a safe-area location. Connect the power supply to the appropriate terminals (refer to the manual for specific terminal numbers). The green power indicator will confirm operation. After that, connect hazardous-area switches or proximity detectors to the input terminals. For NAMUR proximity detectors, no additional resistors are required. For dry contact switches with LFD enabled, add the required series and parallel resistors. Alternatively, disable LFD by linking terminals 7 and 8. Then connect the safe-area load to the relay output terminals. Select the desired phase reversal using the switch on top of the unit. The LED illuminates when the output circuit is closed. For reactive loads, install adequate suppression across the load.

What is in the Box

Please inspect all items upon delivery.

• MTL3011 isolated repeater with relay output.

• Terminal connector blocks.

• Replacement fuse (50mA, 5 x 20mm).

• Installation instruction manual.

Frequently Asked Questions (FAQ)

1. What is the difference between the MTL3011 and similar models?
The MTL3011 provides a relay output for general use. Other similar units may have solid-state outputs. The relay is suitable for AC or DC loads up to 200V.

2. What types of input devices work with the MTL3011?
The MTL3011 works with NAMUR/DIN 19234 compliant proximity detectors. In addition, it works with dry contact switches when suitable resistors are fitted or when LFD is disabled.

3. How does line fault detection work on this device?
The MTL3011 detects open-circuit (Iin < 100µA) and short-circuit (Iin > 6.5mA) conditions. A detected line fault opens the output relay and signals an alarm condition.

4. What hazardous area certifications does this unit hold?
The MTL3011 is certified for switches in Zone 0, IIC, T6 hazardous areas. For proximity detectors, it is certified for Zone 0, IIC, T4-6 hazardous areas (when suitably certified).

5. Can I disable the line fault detection feature?
Yes. You can disable LFD on the MTL3011 by linking terminals 7 and 8. This is useful when using simple switches without adding resistors.