Product Overview

The MTL4014 enables safe-area load control through a hazardous area proximity detector or switch. A reed relay performs the actual switching function. Additionally, a separate reed relay signals line fault conditions. This unit complies with NAMUR and DIN 19234 standards. For this reason, it works perfectly with both proximity detectors and mechanical switches. However, switch-type sensors require suitable resistors added to the circuit. Notably, the line fault detection (LFD) function cannot be disabled. In practice, the MTL4014 provides intrinsic safety for Zone 0, IIC, T6 hazardous areas.

Technical Specifications

General Specifications

• Number of Channels: One

• Hazardous Area Location (Switch): Zone 0, IIC, T6 or Div.1, Group A

• Hazardous Area Location (Proximity Detector): Zone 0, IIC, T4–6 (if suitably certified) or Div.1, Group A

• Voltage Applied to Sensor: 7.0V – 9.0V dc from 1kΩ nominal

• Power Requirement (Vs): 45mA at 24V dc, 50mA at 20V dc, 36mA at 35V dc

• Power Dissipation: 1.1W at 24V, 1.3W at 35V

• Isolation: 250V ac between safe and hazardous area circuits

Input/Output Characteristics

Output closes when input exceeds 2.1mA (below 2kΩ). Output opens when input drops below 1.2mA (above 10kΩ). Hysteresis measures 200µA (650Ω) nominal. These values follow NAMUR and DIN 19234 standards for proximity detectors. As a result, the MTL4014 provides reliable switching with clear thresholds.

Line Fault Detection (LFD)

The MTL4014 opens both the line fault relay and the channel relay under specific fault conditions. For instance, a broken line causes input below 50µA. A shorted line causes input below 100Ω. Consequently, you receive immediate fault notification. However, remember that switch-type sensors must have resistors fitted as shown in the diagram. Importantly, LFD cannot be disabled on this model.

‘No-Fail’ Earth Fault Protection

Earth fault detection on either line becomes available by connecting an external device. Specifically, you link terminal 6 to an MTL4220 earth leakage detector. When a fault occurs on either line, the unit continues working normally. Therefore, process uptime remains protected even during earth fault conditions.

Relay Output Characteristics

The MTL4014 uses a single-pole on/off relay that opens when de-energised. Response time reaches 2ms maximum. Contact rating is 10W, 0.5A, 35V (dc). Contact life expectancy is 10 million operations at maximum load. For reliable operation, reactive loads must be adequately suppressed.

LED Indicators

Three LED indicators provide clear visual status. An amber LED lights when the output circuit is closed. A red LED lights when a line fault is detected. A green LED indicates power is present. As a result, troubleshooting becomes quick and intuitive.

Safety Description & Entity Parameters

• Safety Description: 10.5V, 800Ω, 14mA

• FM Entity Parameters: Voc = 10.5V dc, Isc = 14mA, Ca = 2.4µF, La = 165mH

Terminal Functions

Environmental & Performance Features

• Hazardous Area Compatibility: Zone 0, IIC, T6 and Div.1, Group A

• Response Speed: 2ms maximum switching time

• Line Fault Detection: Automatic with both relays opening on fault

• NAMUR Compliance: Follows DIN 19234 standards

• Earth Fault Protection: Optional via MTL4220 connection

Installation Guidelines

Follow these steps for proper installation of the MTL4014.

1. Mount the unit in a safe-area enclosure away from moisture.

2. Connect the supply voltage to terminals 13 (-ve) and 14 (+ve).

3. Wire the input sensor to terminals 1 (-ve) and 2 (+ve).

4. Add resistors to mechanical switches as shown in the diagram.

5. Connect the output load to terminals 7 and 8.

6. Wire the line fault signal to terminals 10 and 11 if needed.

7. Link terminal 6 to an MTL4220 for earth fault detection (optional).

Note: The MTL4014 has LFD always enabled. For this reason, always fit resistors to mechanical switches to prevent false fault alarms.

Packaging List

• One MTL4014 Relay Interface module

• One product quick start guide

• One terminal connector set

• One anti-static protective bag

Common FAQs

1. Can I disable line fault detection on the MTL4014?

No, the MTL4014 has LFD permanently enabled. Therefore, you must fit resistors to mechanical switches as shown in the circuit diagram. Otherwise, the unit will report false faults.

2. What types of sensors work with the MTL4014?

This unit works with NAMUR proximity detectors and mechanical switches. For proximity detectors, no additional components are needed. For mechanical switches, however, you must add resistors to enable proper LFD operation.

3. How fast does the MTL4014 respond to input changes?

Response time is 2ms maximum. Consequently, this relay interface suits high-speed switching applications. Examples include fast counting or emergency shutdown circuits.

4. Does the MTL4014 provide earth fault protection?

The unit supports ‘no-fail’ earth fault protection when connected to an MTL4220 earth leakage detector. Simply wire terminal 6 to the MTL4220. The MTL4014 continues working normally even during an earth fault.

5. What is the maximum load for the output relay?

The relay contacts rate at 10W, 0.5A, and 35V dc. Contact life expectancy reaches 10 million operations at this maximum load. However, you must adequately suppress any reactive loads to avoid contact damage.

Why Choose This Module?

The MTL4014 simplifies hazardous area switching with built-in line fault detection. It eliminates the need for external fault monitoring circuits. Additionally, the reed relay provides fast, reliable switching. NAMUR compliance ensures compatibility with standard proximity detectors. For applications requiring earth fault detection, simply add an MTL4220. In summary, the MTL4014 delivers safety, speed, and fault visibility in one compact package.