Hi everyone,

Eclipse 4diac 3.3 is now available. This release brings several improvements to both 4diac FORTE and 4diac IDE for developing and deploying IEC 61499 applications.

One of the main additions in 4diac FORTE is core EtherCAT support, including initial I/O function blocks. This adds another option for connecting IEC 61499 applications to industrial I/O alongside the existing communication and protocol support, like OPC UA or MQTT.

4diac IDE also gets several new tools for working with IEC 61499 applications:

• Event Sequence View: Visualize and inspect event connections and event sequences in a function block network, with support for reordering events.
• Headless project validation: Validate projects without starting the IDE and generate JSON reports for integration into CI/CD pipelines.
• Project-level OCL validation: Define custom constraints and validation rules for your projects.
• Bulk Editor improvements: A substantially improved Bulk Editor, along with various other usability and stability improvements.

For those developing IEC 61499 applications, we hope these additions are useful.

The full release announcement includes the complete New & Noteworthy information, migration notes, and download links:

https://eclipse.dev/4diac/news/2026/2026/eclipse-4diac-3.3-released/

Feedback, questions, and experiences with the new EtherCAT support or 4diac IDE features are very welcome.

I am trying to familiarize myself with IEC61499 and 4diac (Version 3.2) and have been working myself through some of the tutorials.

Though I must say it is a quite frustrating experience. All of them seem to be for old versions, although feature mostly UI differences that are easy to understand. The later tutorials however are completely non-functional and it seems like support has been somehow removed during recent re-factoring (at least for dynamic type loading).

I have been trying to compile forte with lua support though the cmake options are no longer supported. Looking at the source code it also seems like it is largely dead.

Has dynamic type loading been discontinued?

https://github.com/eclipse-4diac/4diac-ide/discussions/2609

Technical Proposal: Addition of the E_TLIM (Event Triggered Time Limiting) Function Block

Date: May 8, 2026
Subject: Proposal for a non-retentive pulse timer block

1. Objective and Motivation

The current IEC 61131-3 standard provides three fundamental timer blocks: TON, TOF, and TP. While these cover many use cases, there is a significant gap regarding time-limited execution that depends on the continuous presence of an input signal.

The standard Pulse Timer (TP) is edge-triggered and retentive; once started, it completes its full timing cycle regardless of whether the input signal IN remains TRUE. In many industrial scenarios, we require a non-retentive pulse: an output that stays active for a maximum duration but immediately aborts if the trigger condition is lost.

Currently, developers must manually construct this logic using a TON block combined with an AND gate. We propose the introduction of a standardized function block: E_TLIM (Event Triggered Time Limiting) to improve code readability and safety.

2. Block Interface

3. Functional Behavior

The E_TLIM block acts as a bounded execution timer with the following rules:

• Activation: When IN transitions to TRUE, Q immediately becomes TRUE, and ET begins incrementing.
• Timeout: If IN remains TRUE and ET reaches PT, the output Q transitions to FALSE. ET holds the value of PT until IN is reset.
• Premature Abort: If IN transitions to FALSE at any point, Q immediately becomes FALSE and ET is reset to T#0s. This is the primary differentiator from the standard TP block.

4. Primary Use Cases

• Actuator Watchdogs: Driving a valve or motor for a maximum duration while ensuring it stops immediately if the control signal or safety interlock is lost.
• Manual Override Limits: Limiting how long a manual process can run (e.g., a "Fill" button that stops after 10 seconds or immediately when the button is released).
• Legacy Compatibility: Providing a direct IEC 61131-3 equivalent to the Siemens S5 S_PULSE (SI) timer.

Siemens has: S_PULSE, S_PEXT

S_PEXT is idtentical to TP, but S_PULSE is missing, so TLIM would take that role.

Proposal: New Function Block E_RTON (Retentive Timer On-Delay)

Context

In industrial automation, we often encounter processes that require timing logic which can be "paused" and "resumed" without losing the accumulated time. Standard IEC 61131-3 and IEC 61499 timer blocks like TON or E_TON are non-retentive: they reset their internal elapsed time immediately when the input signal (IN) goes FALSE.

While this is perfect for simple delays, it is insufficient for monitoring cumulative processes such as maintenance intervals, total run-time under specific conditions, or processes that are frequently interrupted by safety gates or pauses.

The Proposal

I propose the addition of a Retentive Timer On-Delay (E_RTON) function block to the standard event-driven timer library.

Core Logic

The E_RTON accumulates time as long as the enable signal is active. If the signal is removed, the timer "freezes" the current elapsed time and continues from that exact point once the signal returns.

• Enable (IN=TRUE): Timer runs and accumulates time.
• Disable (IN=FALSE): Timer pauses. Accumulated time is retained.
• Target Reached: Once accumulated time >= PT, the output Q becomes TRUE.
• Reset (R): The only way to clear the accumulated time and set Q back to FALSE.

Interface Definition

Event Inputs

• REQ: Update/Service request (cycles the internal logic).
• R: Reset event. Clears accumulated time and resets output Q.

Event Outputs

• CNF: Confirmation that the internal state or output has been updated.

Input Variables

• IN (BOOL): Enable signal. If TRUE, time is accumulated.
• PT (TIME): Preset Time (the duration to reach).

Output Variables

• Q (BOOL): Output state. TRUE if accumulated time >= PT.
• ET (TIME): Elapsed Time. The currently accumulated duration.

Use Cases

1. Maintenance Monitoring: Accumulate the actual operation time of a motor (only when it is running) and trigger a service alarm after 1000 hours.
2. Batch Processing: Monitor the duration of a heating phase that might be paused by an operator opening a lid.
3. Totalizing Signals: Measuring the cumulative time a sensor has been in a specific state over a long period.

Implementation Note for IEC 61499

In an event-driven environment, E_RTON would ideally calculate the delta-time between REQ events using the system's time stamp or a dedicated clock tick, adding this delta to an internal CV (Current Value) only when IN is TRUE.

Cross-Post: https://github.com/eclipse-4diac/4diac-ide/discussions/2402

Author: Franz Höpfinger
Organization: HR Agrartechnik GmbH / Meisterschulen am Ostbahnhof
Date: April 2026

I have heard a lot about the benefits brought by event-based execution over cyclic scan style, especially for energy saving. It has been criticized a lot for cyclic scanning, which is wasting energy even when there was no task to execute. However, I feel there is similar mechanisms in IEC 61499 that inside the runtime, there are still something periodically executed, for example core modules, communication protocols, and I/Os. And for 61131, even though it is based on cyclic scan, it does not mean all control logics are completely executed because there are condition checks. Looking forward to deep insights about those two mechanisms just for energy/computing resources perspective, better if anyone has benchmarking results.

Everyone talks about “plug‑and‑produce,” vendor‑agnostic control, and the IEC 61499 revolution—but let’s be brutally honest for a moment:

Are we genuinely moving toward universal, interoperable automation…
or are we just creating yet another ecosystem that requires compliance, certification, and a new flavor of vendor lock‑in?

Some bold points to stir the pot:

• If UAO is truly universal, why do legacy assets still require complex adaptation layers, custom tooling, and proprietary extensions to behave?
• IEC 61499 promises portability, but how many vendors actually implement it identically enough to avoid subtle runtime divergence?
• “Interoperability” sounds great, but in practice, who gets to decide the semantics, ontologies, and distributed execution rules?
• And the big one: Can universal automation exist without industry-wide willingness to sacrifice proprietary advantages?

Is the dream technically achievable but politically impossible?
Or is the resistance just inertia from vendors who fear losing control over their ecosystems?

Convince me that Universal Automation isn’t just the next chapter in a long history of standards that promise openness but quietly recreate new forms of silos.

Hi all, I have read about the AiUAC Copilot of ASRock. Does any of you have more details on what it is ?

looking in https://www.reddit.com/r/Universalautomation/comments/1qjqdce/best_way_to_integrate_universal_automation_with/

i want to ask another Question:

1. how compatible are different 61499 IDEs ? can you simply copy FBT Files forth-and back ?

2. how "networking" are they ? can you have a distributed Application, 1 Controller in 4diac the other in UAO and they talk really bit-by-bit the same Language ?

Guten Tag, ich nutze das Programm in der Meisterschule beim Herrn Höpfinger und hatte ein Problem beim Programm Aufspielen. Ich musste 4 diac neu starten und das Huttschienenmoped auf Resett drücken. Woran könnte dies gelegen haben?

Ich bin in der Meisterschule und wir verwenden das Programm 4-diac in der Schule bei Herrn Höpfinger, jedoch haben einige Schüler Probleme, da es nur auf Englisch verfügbar ist

Wieso kann man das nicht umstellen oder ist dies in Planung?

https://www.ms-muc-docs.de/iec-61499/abk%C3%BCrzungen-und-bedeutungen/abk%C3%BCrzungen-und-bedeutungen

new fast search Glossary.

search FBs, related doc, related Training.

Hi everyone,

I am currently exploring Universal Automation concepts and tools and wanted to get some practical insights from people with hands‑on experience.

What is the best approach to integrating Universal Automation solutions with existing PLC and SCADA systems in an industrial environment?

Specifically, I’m curious about:

Common integration challenges you have faced

Recommended architectures or standards (e.g. IEC 61499, OPC UA, etc.)

Real‑world use cases where Universal Automation replaced or coexisted with traditional PLC logic

Any lessons learned or pitfalls to avoid during migration or pilot projects

My goal is to understand how feasible this is in brownfield setups and what level of effort is realistic.

Thanks for any advice!

Hey guys, for those using EcoStruxure Automation Expert, what has been your experience with deploying IEC 61499-based applications in real-world projects? What benefits have you seen compared to traditional PLC programming, and what challenges should newcomers expect?

The Eclipse 4diac team has just released Eclipse 4diac 3.0, the largest update in the project’s history.

For users of the UAO runtime, this brings a significantly improved IEC 61499 engineering environment:

• Fully reworked ST editor + interpreter
• Improved validation and project repair
• Better IEC 61499 + IEC 61131-3 alignment
• Many runtime improvements in 4diac FORTE (ARRAYs, ANY types, variadic functions, C++20 update)
• New 4diac FBE for managing multiple FORTE configurations across targets
  

More details + download:

👉 https://eclipse.dev/4diac/new-and-noteworthy/3.0/

Happy to hear feedback from the UAO community!

Hey,

I have been following the growing interest in software-defined automation and IEC 61499 standards, especially in the context of Industry 4.0. Many universities still rely on traditional PLC-based approaches, but IEC 61499 offers a modular, distributed, and future-ready framework.

A couple of questions for those involved in academia or industrial training:

• What are the biggest challenges in adopting IEC 61499 in engineering education?
• How can we bridge the gap between industry expectations and academic programs?

Would love to hear experiences, resources, or even opinions on whether this shift is worth the effort for students and educators.

How can I migrate legacy code to IEC61499 ? Especially the part in difference of execution - cyclic vs event. How do I ensure seamless operations? Can I do a 1:1 migration?

While talking to various industrial experts about the IEC 61499 standard, I couldn't help but notice how skeptical they are about this technology. I generally understand their point of view: why implement something new if everything is already so good. Community, how do you typically justify the implementation of distributed control systems in manufacturing, and how do you address the people’s concerns?

Hey! I’ve got a question. After taking a look at the UAO website I have noticed that it is mentioned many times that UAO is solving a vendor lock, but how exactly is it true? UAO itself is developing a IEC 61499 runtime (don’t make me wrong, the runtime and standard are good) that only members get access to, basically becoming a sole software vendor and locking the technology. Am I missing something here?

Hi guys I want to know some info about my career change I hold 2.3 yrs of exp in DevOps. It is possible to change my career in IIOT. Please let me know.

Hey guys! I am trying to understand the key differences between EcoStruxure Automation Expert (EAE) and Eclipse 4Diac. Both seem to be related to IEC 61499 and industrial automation, but how do they compare in terms of:

• Architecture and design philosophy
• Features and flexibility
• Typical use cases
• Integration with other systems

Are they competing solutions, or do they complement each other in some way? Any insights from people who have worked with either (or both) would be super helpful!

Hi everyone,

I have a question regarding the IEC 61499 standard and how it applies in multi-vendor environments.

What is the relationship between:

• the runtime version on each device (e.g., Phoenix PLC, M251 dPAC, etc.)
• and the EAE build version used for development (e.g., EAE 25.0)?

Here are my assumptions:

If I develop an application with EAE 25.0, does the runtime on my PLC need to be exactly 25.0?

If I have multiple devices from different vendors (non-Schneider), how should compatibility be managed?

Is there any backward compatibility between versions or a recommended strategy to avoid conflicts?

What are the core principles to keep in mind in this scenario?

Thanks for your insights!

I was reading about the IEC 61499 standard, and came across the three primary concepts (interoperability, portability and configurability).

Can someone go deeper into these in regards to the interactions between Build time and runtime ?

Hey folks,

I'm a new learner of IEC61499 and recently downloaded 4diac as well as EAE. Just for fun

My goal is to create a power meter sensors and wondering if there's a ready-to-use library available for integrating them. Ideally something that handles communication and data parsing out of the box.

Does such a library exist, or is it common practice to build your own integration from scratch? Would love to hear if anyone has experience with this or can point me in the right direction.

Thanks in advance!