The TSX-LES74 is a remote I/O junction module used to extend the reach of a Modicon Premium PLC’s control system. It acts as a connection and communication hub between a central PLC and a bank of additional I/O modules located far away in the field, eliminating the need for long, expensive runs of individual sensor and actuator cables.
Key Identifier: “Remote Derivative JUNCTION” on the label means it is the base unit that creates a remote I/O drop on a network.
Detailed Product Description
1. Primary Function:
The TSX-LES74 serves as the head of a remote I/O station. It connects to a communication network (like FIPIO or Modbus Plus) on one side and hosts up to 7 additional “derivative” I/O modules (TSX-DExxx, TSX-DSxxx, TSX-DAx, etc.) on the other. It manages the data exchange between these I/O modules and the central processor.
2. Key Features:
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Communication Interface: It features a FIPIO network connector. FIPIO (Factory Instrumentation Protocol I/O) was Schneider’s high-speed, deterministic fieldbus for the Premium range.
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Integration: It can also be integrated into Modbus Plus networks using a specific network interface module (TSX-MBP100).
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Local Expansion: The module has a backplane that supports up to 7 additional I/O modules (such as digital inputs/outputs, analog inputs/outputs, counters, etc.) directly next to it.
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Power Supply: The entire remote drop, including the TSX-LES74 and its I/O modules, requires a separate power supply (e.g., TSX-PSPxx or TSX-PSRxx series).
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LED Indicators: The unit features status LEDs (OK, RUN, COM, I/O) for quick diagnostics of the module’s health and communication status.
3. Technical Specifications:
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Product Range: Modicon Premium
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Module Type: Remote Derivative Junction
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Number of Local Drop Slots: 7
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Communication Network: FIPIO (Primary), Modbus Plus (via gateway)
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Power Supply: 24 VDC (typically supplied by a separate TSX-PSRxx or TSX-PSPxx power module)
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Compatibility: Designed to work with Modicon Premium PLCs (TSX-P57, etc.) and their associated programming software (Unity Pro).
4. Typical Application & Use Case:
Imagine a large conveyor system in a factory.
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The main control cabinet with the Premium PLC is in the main control room.
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A motor starter and several sensors are 200 meters away at the loading bay.
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Instead of running dozens of wires 200 meters back to the main cabinet, you install a remote I/O station with the TSX-LES74 at the loading bay.
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You plug a digital output module (e.g., TSX-DSY16T2) into the LES74 to control the motor starter, and a digital input module (e.g., TSX-DEY16D2) to read the sensors.
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A single, robust FIPIO network cable is then run from the main PLC to the TSX-LES74, carrying all the control and data signals for that entire area. This saves significant cost, wiring time, and complexity.
5. Status: Legacy / Discontinued
Important Note: The Modicon Premium platform is considered a legacy product line. While still widely used in many existing industrial installations, it has been largely superseded by the newer Modicon M580 ePAC (Ethernet Programmable Automation Controller) platform.
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For New Projects: Schneider Electric strongly recommends using the Modicon M580 and its associated Ethernet-based I/O (e.g., X80 drops) for new system designs.
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For Existing Systems: The TSX-LES74 and its modules are typically only sourced on the aftermarket or refurbished market for maintenance, repair, or minor expansion of existing Premium systems.
