Sample of an IEC 61850-8-3 request-response message sequence using JSON

The standard IEC 61850-8-3 under preparation will use ASN.1 JER (JSON) encoding. In order to understand, what that means check the following message sequence of the service (copied from the Wireshark trace, without WebSocket, TCP/IP, ... headers).

Note that you can use the Open Source Software of the PoC (Proof of Concept) to let client and server exchange real messages ... enjoy!

getLogicalDeviceDirectory

    { "request": {

            "associateId": "cp1",
            "invokeId": 1,
            "service": {
                "getLogicalDeviceDirectory": {
                    "ldName": "LD0"
                }}}}

    { "response": {
            "associateId": "cp1",
            "invokeId": 1,
            "service": {
                "getLogicalDeviceDirectory": {
                    "lnName": [
                        "LLN0",
                        "LPHD1",
                        "DWMX1",
                        "DGEN1",
                        "MMXU1"
                    ]}}}}

setDataValues

   {"request": {

            "associateId": "cp1",
            "invokeId": 56,
            "service": {
                "setDataValues": {
                    "ref": {
                        "ref": "LD0/LLN0.Mod.ctlModel",
                        "fc": "cf"
                    },
                    "dataAttrVal": [
                        {
                            "data": {
                                "enumerated": "2"
                           }} ]}} }

    {"response": {
            "associateId": "cp1",
            "invokeId": 56,
            "service": {
                "setDataValues": null
            }}}

    

Any question? Guess there is likely no need to ask, what this is ...

Search for "8-3".

Is IEC 61850 an old Standard?

What do you think? It depends ... IEC 61850 is a standard series of many parts ... published in different years ...

The other day I was reading that somebody on LinkedIn beliefs that IEC 61850 is old ... Oops. Here is what I answered:

I was involved in the development of MMS (ISO 9506, starting mid 1980s), later in ICCP (TASE.2, IEC 60870-6, using MMS), then IEC 61850 (starting 1995, using as well the "old" MMS). 

The AC interconnected power systems have been developed more than 130 years ago ... and improved since then ... AND: Yet we do not complain that they are OLD. They have done a great job. Old wine may be better than young wine ... or?

The standard series IEC 61850 has many aspects to consider: 

• System Configuration Language (SCL, IEC 61850-6) is brand new! 
• GOOSE and sampled values are brand new! 
• The many standard "signals" like MMXU.Hz for frequency measurement are old in the sense that frequency is a physical given.
• There is something we may call "old": the use of the "old" MMS as the protocol for client/server communication according to IEC 61850-8-1 (-8-2). ok.
• There is an alternative new web-based solution under way: IEC 61850-8-3 (a new protocol for client/server in IEC 61850 ... WebSocket transport, ASN.1 message schema, ASN.1 JSON encoding rules, and ASN.1 DER encoding rules).

If you want to learn why the Netherlands DSOs initiated the IEC 61850-8-3, check HERE.

A great reply says: "The transport choice is what stands out: MMS was never reachable from a browser, WebSocket with JSON encoding is, which changes what client tooling can be without an install."

There are other brand new parts of IEC 61850 just published, e.g., IEC 61850-7-410 for hydro, gas, and steam power plants.

Are WebSockets the future for real-time communication?

WebSockets provide a way for web browsers and cloud apps to talk directly to devices for automation and monitoring. A WebSockets create a two-way open communication channel. It wraps messages (according to various message schema, e.g. in ASN.1 notation) in web-friendly formats like JSON. This bypasses strict firewall rules without needing complex, heavy software.

WebSockets are used in many solutions like OPC UA, OpenADR, ... and soon in IEC 61850-8-3 (alternative for MMS). 

How do WebSockets perform in a PLC environment where usually special industrial communication protocols are used? An interesting paper discusses this question:

"Latency Analysis of WebSocket and Industrial Protocols ..."

WebSockets are likely to becoming the future standardized web-based "carrier". 

The Netherlands Distribution Service Operator have shown with a PoC (proof of concept, now used for the definition of IEC 61850-8-3) that standardized (!) WebSockets can exchange IEC 61850 standard(!) messages containing data values produced and consumed by the huge amount of standardized (!) IEC 61850 models, configured by a standardized configuration (!) language (SCL, IEC 61850-6), and encoded in a standard (!) JSON format.

Background information can be found in my video

Feedback on LinkedIn: "This presentation made everything much clearer! But seriously, using WebSockets as a transport for industrial protocols is a really good idea."

Free ASN.1 Browser for IEC 61850-8-3 ASN.1 Module from RTI2 PoC

If you want to browse easily the ASN.1 message schema for the new project IEC 61850-8-3 (DSM) underway, check out this free browser: 

https://www.nettedautomation.com/editor

A preliminary asn.1 module for IEC 61850-8-3 (from PoC of RTI2) is available for download:

This is how it looks like:

and ...

The schema is very simple compared to MMS for IEC 61850-8-1.

Let us know if you have any question.

Extended Video on IEC 61850-8-3 Available - Example Messages

 An extended version of the video on  

IEC 61850-8-3
Communication networks and systems for power utility automation –
Specific Communication Service Mapping (SCSM) –
Mapping to Direct Message Specification (DMS), JSON Encoding Rules, and WebSockets 

is available. I have added some five minutes ... total time is 23 minutes.

I have added mainly two examples of services for IEC 61850-8-1 (MMS) and IEC 61850-8-3 (DMS):

The figure above shows how a client can get the list of logical nodes from the server with MMS ... and with DMS:

Details can be watched in the video ... enjoy.

IEC 61850 Series for Any Automation Domain using Electric Power (two Examples)

The standard series IEC 61850 is applicable for simple applications and huge systems. The standard is not restricted to a specific domain. Like electric power is everywhere. So could IEC 61850 be everywhere.

I have discussed this briefly in the context of a LinkedIn post.

Now it's time to discuss briefly two simple applications ... just looking at the two models ... without further explanations.

The German FNN Steuerbox

The Steuerbox is mainly providing schedules for the interface between the grid and the power user:

This model is defined for a special use-case: Steuern (remote control). No need for an engineering tool ... it is just a fixed model ...

The Netherlands RTI (Real-Time Interface) for power generation (> 1 MW)

... this is a fixed model with some details:

The RTI models and services are currently using IEC 61850-8-1 (MMS) communication (RTI 1). The RTI 2 will finally use the IEC 61850-8-3 (DMS) once it is specified. A Task Force has started to specify the new standard in May 2026.

The fixed models allow for a high level of interoperability. The central systems (representing the IEC 61850 clients) can communicate with and IED following these specifications. In the case of the FNN Steuerbox it has been proven that the client application could talk to all steuerboxes in the field without paying attention to which vendors device it is talking to.

REAL INTEROPPERABILITY !!

Why is there an Need for an Additional Service Mapping in IEC 61850 (IEC 61850-8-3)?

The two service mappings for IEC 61850 are IEC 61850-8-1 (MMS) and IEC 61850-8-2 (MMS/XML). The mapping IEC 61850-8-1 is in operation from the first days when IEC 61850 was implemented and used ... all over ... in millions of devices and thousands of systems. Ok ... perfect.

Why is there an need for an additional service mapping in IEC 61850 (IEC 61850-8-3)? 

Simply because of the complex and tricky mapping to MMS (Manufacturing Message Specification, ISO 9506). 

IEC 61850-8-3
Communication networks and systems for power utility automation –
Specific Communication Service Mapping (SCSM) –
Mapping to Direct Message Specification (DMS), JSON Encoding Rules, and WebSockets 

In order to explain details of the new approach to be used for the new work item proposal IEC 61850-8-3 I have produced a 17 minute video (updated version 2026-06-04, 23 minutes).

It is likely that this will become a major shift in the use of IEC 61850.

Enjoy!

The PAC World Magazine Reports From the 30 Year Anniversary of IEC 61850 in September 2025

The 30 year anniversary of IEC 61850 in September 2025 was a big success.

The report mentions me: "The presentations were bracketed by the first one from Karlheinz Schwarz about how all of this started in the past Millenium ..."

I am very thankful for the invitation by Dr. Fred Steinhauser (Omicron) to speak about the history ... 

Click HERE for the Report in the PACW.

Click HERE for more photos and a link to my "Millenium" presentation.

When browsing the Web, I see many more papers, reports, posts, ... on IEC 61850 for substations and for applications beyond substations.

More to come: With IEC 61850-8-3

New Work Item Proposal on IEC 61850-8-3 has been accepted by 95 % of the TC 57 National Committees

In December 2025 the NWIP (57/2866/NP - proposed project number: IEC 61850-8-3) was published for voting and comments:
https://blog.nettedautomation.com/2025/12/long-awaited-christmas-gift-for-smarter.html

Today we are happy that the NWIP has been approved by IEC - only one country disagreed in the voting process.

IEC 61850-8-3
Communication networks and systems for power utility automation –
Specific Communication Service Mapping (SCSM) –
Mapping to Direct Message Specification (DMS), JSON Encoding Rules, and WebSockets 

The result of this work will very likely change the usability of IEC 61850 outside substations.

Stay tuned to follow the progress.

In order to explain details of the new approach to be used for the new work item proposal IEC 61850-8-3 I have produced a 17 minute video (2026-05-13).

IEC 61850: Realtime Interface Version 2.0 - Why This Matters

Netbeheer (the Netherlands organization of Distribution System Operator) published the Realtime Interface version 1.0 (RTI 1) in 2024.

The revised specification (named RTI 2) has been developed last year and proposed to IEC TC 57 as an additional solution for communication of IEC 61850 information (New Work Item Proposal IEC 61850-8-3).

The one page list of good reasons for the new solution 

The combination of IEC 61850 data model / services and WebSocket protocol
Why this matters

can be found here.

See also:
https://blog.nettedautomation.com/2025/12/long-awaited-christmas-gift-for-smarter.html