MTL2000 series intrinsically safe isolation safety barrier

Overall positioning of the product

The MTL2000 series is a classic intrinsically safe (IS) isolated safety interface device used by MTL to connect Zone 0, IIC, T4/T6 hazardous area instruments and safety area control systems, replacing traditional Zener safety barriers. Its core advantages include:

Three party full isolation (input/output/power supply 250V)

No need for high integrity safety grounding

Built in triple protection for wire breakage, ground fault, and power failure

Supports 240V/120V AC or 24V DC power supply

35mm standard rail installation, compatible with MTL3000 series

Common Specification

Key indicators of parameter items

Isolation withstand voltage 1500V rms (safe zone) ↔ Dangerous Zone

Power supply version 240V AC/120V AC/24V DC

Working temperature -20~+60 ℃ (spacing ≥ 5mm); -20~+55 ℃ (close packed)

Installation method: 35mm guide rail/flat installation

Terminal maximum 4mm ² wire with identification position

Installation in a protected safety zone, compatible with an enclosure that can achieve IP65 rating

Certification of global intrinsic safety: Zone 0, IIC, T4/T6

Core models and functions

1) Switch/Relay Class (MTL22xx)

MTL2210B (1-channel switch relay)

Dangerous Zone 1 Switch Control Safe Zone 2 500VA Load

Support self-locking mode (motor start stop)

Response: 50ms; Contact: 2-pole conversion

Disconnection/Power Loss → Relay Power Loss (Safe State)

MTL2211 (2-channel switch relay)

Two independent inputs that do not interfere with each other

Each drive is 500VA, with dual contacts in parallel

Response: 50ms; LED status indicator

MTL2213 (3-channel switch/proximity sensor)

Compatible with NAMUR standard proximity sensors

Support phase reversal (alarm logic reversal)

100VA contact capacity per channel

MTL2215 (Safe Zone → Hazardous Zone Intrinsic Safety Output)

Safe zone switch signal → Control the intrinsic safety circuit of the hazardous zone

The contact is non energy storage type and can be directly connected to Zone 0

2) Analog class (MTL24xx)

MTL2441B (4-20mA relay power supply)

Power supply for 2/3 line transmitters in hazardous areas

Isolate relay 4-20mA signal to safe area

Accuracy:<20 μ A; Temperature drift:<1 μ A/℃

Maximum circuit resistance: 50 Ω Related calculations

MTL2442B (4-20mA isolated drive)

Safety zone 4-20mA → Isolation drive dangerous zone actuator

Maximum load: 800 Ω

Accuracy:<20 μ A; Response: 200ms stable

Protection mechanism

Wire breakage protection: Input line disconnected → Relay power loss/alarm

Ground fault protection: Ground resistance<1k Ω → safe action

Power failure protection: power failure → output reset to safe state

Intrinsic safety current and voltage limiting: ensuring that ignition energy is not generated in hazardous areas

Maximum cable parameters (key)

Model: Maximum capacitance Ca, maximum inductance La

MTL2210B 7μF 47mH

MTL2211 5.5μF 75mH

MTL2213 3μF 165mH

MTL2441B 0.17μF 5.1mH

MTL2442B 0.13μF 4.2mH

Key issue

Question 1: What are the core advantages of MTL2000 series compared to traditional Zener safety barriers?

Answer: The core advantage is the 250V electrical full isolation of input/output/power supply, which does not require high integrity safety grounding and significantly reduces construction costs; Simultaneously integrating triple protection of disconnection, ground fault, and power failure, the system is safer and the wiring is simpler.

Question 2: MTL2213 supports both switches and proximity sensors. How is it compatible with the NAMUR standard?

Answer: MTL2213 provides 7.7-9.0V and 1k Ω internal resistance for the sensor, according to the NAMUR DIN 19234 threshold judgment:

Current>2.1mA=sensor conducting

Current<1.2mA=sensor disconnected

Support phase reversal and flexible setting of alarm logic.

Question 3: How to use MTL2441B and MTL2442B together in analog circuits?

answer:

MTL2441B: Responsible for supplying power to hazardous area transmitters and isolating and relaying signals to safe areas;

MTL2442B: Responsible for isolating the 4-20mA signal in the safety zone and driving the actuator in the danger zone;

The combination of the two can achieve bidirectional isolation and transmission of signals across hazardous areas, while maintaining intrinsic safety and explosion-proof throughout the entire process.