---
title: "SoftdPAC High Availability"
sidebar_label: "Overview"
description: "Understand the redundant SoftdPAC controller pair you will deploy across two Barbara edge nodes, with automatic failover."
lastmod: "2026-07-30"
pagination_prev: null
---

import VersionNotice from '@site/src/components/VersionNotice';
import { UpdateInProgressNotice } from '@site/src/components/VersionNotice';

<VersionNotice platformArticleVersion="v3.3.0" />
<!--
<UpdateInProgressNotice />
-->

## Overview

**SoftdPAC** is Schneider Electric's software PLC, part of **EcoStruxure Automation Expert** and built on the open **IEC 61499** standard. It runs your automation application directly on a Barbara **Edge Node** instead of on dedicated controller hardware, so you decouple your control logic from any single box.

This guide covers the **High-Availability (Standalone)** edition. It runs a **redundant controller pair across two edge nodes** with **automatic failover** over a dedicated **interlink** cable. If the active node goes down, the standby takes over on its own, and when the node returns the pair re-pairs automatically. It runs without the SoftdPAC manager and without EAE-managed commissioning: you install the app on both nodes, set one as primary and one as secondary, and connect from EAE to deploy and run your application.

Security is basic by design. The device self-generates its TLS certificate, which EAE trusts on the first connection. 

<a href="https://market.barbara.tech/application-detail/6a314a24da42b2a9391e7867" target="_blank" class="app-info-link">
  <div class="app-info-box">
    <div class="app-corner-image">
      <img src={require('/img/MarketplaceLogo.png').default} alt="Corner Badge" />
    </div>
    <div class="app-icon">
      <img src={require('/img/SoftdPAC.png').default} alt="Schneider Softdpac High Availability A/B icon" />
    </div>
    <div class="app-details">
      <h3>Schneider Softdpac High Availability A/B</h3>
      <p>Redundant Schneider SoftdPAC (IEC 61499) PLC pair with automatic failover. Simple version without EAE-managed commissioning.</p>
    </div>
  </div>
</a>

<div style={{ maxWidth: '920px', margin: '2em auto 2em auto', textAlign: 'center' }}>
  <img src={require('./img/ha-topology.png').default} alt="Two Barbara edge nodes each running the SoftdPAC PLC on the plant LAN, joined by a dedicated interlink for automatic failover, reached by EAE and OPC UA consumers" className="shadow-img" />
  <figcaption style={{ fontSize: '0.9em', color: '#666', marginTop: '0.6em'}}>
    SoftdPAC HA topology
  </figcaption>
</div>

## What you'll do

You will build the pair from end to end:

1. **Plan the network** — 2 Barbara nodes, the interlink cable, and the LAN addressing, with a plain-language look at `macvlan` vs `ipvlan`.
2. **Deploy the primary node** — install the app on the first node and set the primary role, LAN and clock values.
3. **Deploy the secondary node** — install it on the second node with the mirror values so the pair forms.
4. **Connect from EAE** — add the redundant device and run your IEC 61499 application on the pair.
5. **Verify failover** — force a node failure and watch the standby take over with no loss of control.

By the end, you'll have a redundant PLC pair running your IEC 61499 application on standard Barbara edge hardware, with hands-off failover.

## Summary

You now know what the SoftdPAC High-Availability edition is and what you'll build: a redundant controller pair with automatic failover, managed from one console and reachable on your LAN like any other PLC, on the node's host IP, or over the Barbara VPN. Next, plan the two nodes and the network.

Continue with [Prerequisites and how the network works](/use-cases/deploy-softdpac-ha/prerequisites/).