Wednesday, August 12, 2026

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 ...

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