ETA REX12-TA2-107 Modular Circuit Breaker

ETA REX12-TA2-107 Modular Current Protection Circuit Breaker

1. Model Code Breakdown

Model split: REX12 TA2 107

1. REX12: ETA REX12 series modular current protection circuit breaker (electronic overload protector / miniature electronic circuit protector, DIN rail mounted)
2. TA2: Sub-series functional code, 2-channel universal type for DC and AC, equipped with temperature monitoring and fault signal output
3. 107: Rated current specification code → Rated current 7A
4. Brand Overview

ETA (Swiss ETA): A global brand of industrial electronic protection components, specializing in miniature equipment circuit breakers, electronic overcurrent protectors and thermal-magnetic circuit breakers. Widely applied in industrial control cabinets, robotics, rail transit, photovoltaic energy storage and medical devices.

REX12 Series: Ultra-thin modular electronic protection devices as a replacement for traditional fuses, featuring remote signal feedback and precise segmented current limiting.

III. Core Specifications (REX12-TA2-107)

Electrical Specifications

Rated Current In: 7A

Channels: Dual independent protection channels (separate current limiting and fault alarm for two outputs)

Operating Voltage: Universal for DC 24V / AC 24~230V

Trip Type: Electronic inverse-time overload protection + instantaneous short-circuit cut-off

Signal Output: TA2 standardly equipped with two sets of passive fault contacts (NO/NC, connectable to PLC for fault signal collection)

Mounting: Standard 35mm DIN rail, module width only 12mm per channel

Functional Features

1. Independent circuit protection for dual channels without mutual interference
2. Precise electronic current limiting, eliminating aging issues of traditional fuses
3. Manual reset after overload/short-circuit tripping; no consumable replacement required
4. Remote fault alarm contacts for automated equipment monitoring
5. Low power consumption, ultra-thin design dedicated to dense cabinet wiring
6. Typical Application Scenarios

24V DC output circuit protection for industrial PLCs and servo drives

Branch power supply protection for robot IO modules and sensors

Multi-channel DC power supply protection for medical equipment and test instruments

On-board control cabinets for rail transit and auxiliary circuits of energy storage BMS

1. Reference Alternative Models within the Same Series

REX12-TA2-103: 3A dual-channel

REX12-TA2-105: 5A dual-channel

REX12-TA2-110: 10A dual-channel

REX12-TA1-XXX: Basic single-channel model (without separate dual-channel alarm)

1. Key Distinction Points

TA1 = single channel; TA2 = dual channel with independent fault signals; the last two digits of the three-digit suffix represent rated current (107 = 7A).

Full Technical Analysis of ETA REX12-TA2-107 Electronic Overcurrent Protector

> Note: The previous interpretation of the model suffix “107” was inaccurate.

1. Digit-by-Digit Model Code Decoding

Standard full ordering format: `REX12 TA2 107 DC24V XA/XA`

The provided `REX12-TA2-107` is the abbreviated base model of the series; full purchasing models require supplementary suffix current specifications.

1. Full List of Core Specifications

Electrical Specifications

Mechanical & Mounting Specifications

III. Protection Mechanism & Working Principle

1. Precision Electronic Sampling: Built-in current sensors collect real-time circuit current; a dedicated chip executes inverse-time tripping algorithms. Higher overload multiples lead to faster tripping, precisely matching cable thermal withstand capacity with far lower dispersion than traditional fuses.
2. Microsecond-Level Short-Circuit Cutoff: Upon detection of short-circuit current, semiconductor switches shut down within microseconds to limit fault current rise, preventing surge damage to downstream loads and avoiding tripping of the upstream switching power supply.
3. Fail-Safe Backup Protection: Built-in blade fuses compliant with IEC 60127-4 and UL248-14 standards. When electronic protection components malfunction, the fuse acts as the final safety barrier, complying with EN 60204-1 for machine equipment cable protection.
4. Selective Disconnection: Only the faulty branch is cut off while other branches remain powered, greatly improving system availability and avoiding full power supply shutdown caused by single-point faults.
5. Installation Wiring & System Configuration

Power Distribution Connection

Power input is uniformly connected via EM12-T power distribution modules. Side bridging arms enable parallel power supply between modules without additional jumper wires. A single set of distribution modules supports up to 16 parallel protection modules; matched PM12-T potential expansion modules enable separate GND circuit routing.

Load & Signal Wiring

Load Side: One set of Push-in terminals per channel for direct connection to load positive circuits; wire stripping length: 8~10mm.

Signal Side: Independent fault signal output terminals per channel, connectable to PLC DI modules for remote fault monitoring and alarm.

Installation Precautions

Mount modules vertically on DIN rails with at least 10mm clearance above for heat dissipation.

AC voltage input is strictly prohibited; the device is only applicable to 24V DC systems.

1. Safety Certifications & Compliance Standards

UL 508 Certification for Industrial Control Equipment

UL 2367 Solid-State Circuit Breaker Certification

cULus Dual Certification for Canada & the United States

EN 60204-1 Electrical Equipment Standard for Machinery (cable protection compliance)

IEC 60127-4 Miniature Fuse Standard (backup fuses)

RoHS Environmental Compliance

1. Model Selection Comparison within the Same Series

VII. Typical Application Scenarios

Branch protection for 24V DC power distribution systems in industrial control cabinets

Power supply protection for field components including PLC IO modules, sensors, solenoid valves and indicator lamps

Automated production lines, robot control cabinets and semiconductor manufacturing equipment

Auxiliary circuits of new energy storage BMS and on-board control cabinets for rail transit

Multi-channel low-voltage power supply protection for medical testing equipment and laboratory instruments

VIII. Common Fault Troubleshooting Matrix

1. Terminal Pinout & Wiring Definition

The REX12-TA2-107 adopts a system-level bridging architecture. Power input is connected in parallel via side-mounted matching EM12-T power distribution modules, while load and signal terminals are wired directly on the front face. Terminals are divided into three major functional zones:

1. Terminal Zones & Pin Definitions

From top to bottom on the module front (operation side), terminals are divided into power bridging zone, load output zone and signal output zone. Detailed pin definitions are as follows:

> Core Note: This model is a positive-side protection type, which only cuts off the load positive circuit while the negative circuit remains continuously connected. Fault signals are low-level active (NPN type), directly compatible with DI input modules of mainstream PLC brands including Siemens and Mitsubishi.

2. Wiring Specifications & Precautions

All terminals are Push-in spring terminals; wires can be inserted or removed by pressing the orange release button without tools.

The module must be installed side-by-side with EM12-T series power distribution modules to receive operating power; standalone modules cannot be powered on.

A single EM12-T distribution module supports up to 16 parallel REX12 protection modules with total current not exceeding 40A.

No additional current limiting required for capacitive load startup; each channel supports shock-free startup of capacitors up to 20000μF.

Inductive loads (solenoid valves, relays) require freewheeling diodes connected in parallel on the load side to prevent reverse voltage breakdown of internal MOSFETs.

1. Cross-Brand Compatible Replacement Solutions

The ETA REX12 series adopts a proprietary bridging power distribution architecture, with no cross-brand models offering 1:1 fully compatible pinouts. Two replacement categories sorted by ascending replacement cost are listed below:

Solution 1: Same Footprint Functional Replacement (Retain DIN Rail Space, Replace Distribution & Protection Modules)

Suitable for cabinets with limited space where the 12.5mm dual-channel width must be maintained; power distribution modules also require simultaneous replacement.

Solution 2: Independent Dual-Channel Functional Replacement (Direct Complete Unit Replacement, No Matching Distribution Modules Required)

Suitable for scenarios where the original REX12 power distribution system is not retained and independent wiring is adopted; higher integration and more flexible wiring.

Key Replacement Reminders

1. Power Distribution Architecture Difference: The side bridging power supply of REX12 is an ETA patented design; all other brands adopt independent terminal wiring, requiring re-routing of power input lines during replacement.
2. Signal Type Matching: REX12 outputs NPN open-collector signals; confirm the signal output type (NPN/PNP/passive contact) of replacement models to match the existing PLC system.
3. Tripping Characteristics: All alternative models feature electronic inverse-time overload protection and instantaneous short-circuit cutoff, with protection curves basically consistent with REX12 for direct replacement.