Complete Guide to Programming IDEC PLCs with WindLDR

Quick Answer

IDEC MicroSmart PLCs, including the FC6A and FC5A series, are programmed using WindLDR software. WindLDR supports ladder logic, function block diagram, and structured text programming languages and includes built-in tools for Modbus RTU/TCP communications, analog I/O configuration, PID control, and data logging. IDEC PLCs are widely used in HVAC, building automation, light industrial, and oilfield control applications.

What Is IDEC?

IDEC Corporation is a Japanese automation manufacturer founded in 1945 in Osaka. IDEC produces compact PLCs, HMI touch panels, safety relays, switches, and sensors for industrial automation. Their MicroSmart PLC line is positioned as a cost-effective alternative to Allen-Bradley Micro800 and Siemens S7-1200 for applications requiring compact controllers with built-in analog I/O, serial and Ethernet communication, and free programming software.

MicroSmart PLC Family

FC6A (MicroSmart All-in-One)

The FC6A is IDEC's current flagship compact PLC. It features an all-in-one base unit with built-in discrete and analog I/O, expansion capability up to 512 I/O points, onboard Ethernet and serial ports, SD card data logging, and a real-time clock. CPU variants include Slim (16 I/O), Plus (24-40 I/O), and Communication types with additional serial ports.

FC5A (MicroSmart)

The FC5A is the predecessor to the FC6A, still widely installed in existing systems. It uses the same WindLDR programming software but with a smaller instruction set and fewer expansion options. The FC5A is suitable for simple discrete control and basic analog applications.

FC4A (MicroSmart Pentra)

The FC4A is a legacy entry-level platform. While still supported by WindLDR, new designs should use the FC6A for its superior I/O flexibility, communication options, and processing power.

WindLDR Software Overview

WindLDR is IDEC's PLC programming environment, available as a free download from the IDEC website. Unlike competing platforms that require paid licenses (Rockwell's Studio 5000, Siemens TIA Portal), WindLDR has no license fee or activation requirement. WindLDR runs on Windows and provides ladder diagram, function block diagram, and structured text editors, a built-in simulator, device monitor for online debugging, and configuration dialogs for all FC6A special functions.

Supported Programming Languages

• Ladder Diagram (LD) — The primary language for IDEC PLCs. Uses contacts, coils, timers, counters, and math instructions in a familiar relay-logic format.
• Function Block Diagram (FBD) — Graphical block-based programming suited for analog signal processing, PID control, and continuous process logic.
• Structured Text (ST) — High-level text-based programming for complex calculations, data manipulation, and sequencing algorithms.

Communication Options

• Modbus RTU — Serial communication (RS-232/RS-485) for connecting meters, drives, and field instruments.
• Modbus TCP — Ethernet-based Modbus for SCADA integration and networked device communication.
• EtherNet/IP — Adapter mode for integration with Allen-Bradley and other EtherNet/IP-capable controllers.
• BACnet MS/TP — Building automation protocol support for HVAC applications.

IDEC in HVAC, Building Automation, and Oilfield Applications

• HVAC — Air handling unit control, chiller sequencing, economizer logic, and building pressure control using FC6A onboard analog I/O and BACnet communication.
• Building automation — Lighting control, access control sequencing, elevator logic, and energy management with data logging to SD card.
• Light industrial — Packaging machines, conveyor control, labeling systems, and small batch processes.
• Oilfield — Wellsite pump control, tank level monitoring, chemical injection metering, and small RTU replacement applications where a compact, cost-effective controller with Modbus communication is needed.

WindO/I-NV4 HMI Integration Overview

IDEC's HG series touch panels are programmed using WindO/I-NV4 software (also free). The HMI connects to the FC6A via USB, serial, or Ethernet and provides operator interface screens with numeric displays, buttons, trend charts, and alarm lists. See the HMI integration guide for setup details.

Getting Started

New to IDEC WindLDR? Follow these guides in order:

1. What Is the IDEC FC6A? Hardware Overview
2. Installing WindLDR and Connecting to the FC6A
3. WindLDR Interface Overview
4. Ladder Logic Basics
5. Data Types and Memory Map Reference
6. Analog Input and Output Configuration

Sub-Article Index

Explore the full IDEC WindLDR knowledge cluster:

• What Is the IDEC FC6A MicroSmart PLC?
• WindLDR Installation and Setup
• WindLDR Interface Overview
• Ladder Logic Basics
• Function Block Diagram Programming
• Structured Text Programming
• Data Types and Memory Map Reference
• Analog Input and Output Configuration
• PID Control Configuration
• Modbus RTU Configuration
• Modbus TCP Configuration
• HMI WindO/I-NV4 Integration
• Data Logging with SD Card
• Program Upload, Download, and Monitoring
• Fault Diagnostics and Troubleshooting