Node-red-contrib-buffer-parser with BIHL WIEDEMANN

General
1

Respected Steve Sir,

I have a doubt regarding the data output from the Node red Config buffer parser.

  1. I am using SMC pressure Sensor IO link and I configure it on the PORT 1 (There are 04 ports on IO Link Master starting from PORT 01 and goes to PORT 04) and I gave 2 bytes of process data as described by SMC vendor.

PROCESS DATA STRUCTURE FOR SMC
PROCESS DATA STRUCTURE FOR SMC1280×720 60.8 KB

SMC PROCESS DATA STRUCTURE
SMC PROCESS DATA STRUCTURE1882×921 131 KB

Parser node details with right shift by 3
Parser node details with right shift by 31920×1080 279 KB

Pressure Sensor Values
Pressure Sensor Values1536×864 259 KB

  1. When I configure it to the PORT 01 I get the desired results.
    Now I shift the sensor from PORT 01 to PORT 03 and try to read values and I read nothing.

PORT 3 CHANGED FOR SMC SENSOR
PORT 3 CHANGED FOR SMC SENSOR1920×1080 120 KB

When I was reading correctly at PORT 1 i kept the offset = 0 and when I configured it to PORT 3 I keep the offset= 10 as I am reading data from BYTE 10.

PORT 3 in NODE RED
PORT 3 in NODE RED1919×929 123 KB

May be I am doing something wrong with the "offset" can anyone please guide me in this matter

?

Please check the flow as mentioned below :slight_smile:

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    {
        "id": "166bcf76d196177e",
        "type": "buffer-parser",
        "z": "d46daf54501e291d",
        "name": "",
        "data": "payload",
        "dataType": "msg",
        "specification": "spec",
        "specificationType": "ui",
        "items": [
            {
                "type": "int16le",
                "name": "pressureSensorValue",
                "offset": 10,
                "length": 1,
                "offsetbit": 0,
                "scale": ">>3",
                "mask": ""
            }
        ],
        "swap1": "",
        "swap2": "",
        "swap3": "",
        "swap1Type": "swap",
        "swap2Type": "swap",
        "swap3Type": "swap",
        "msgProperty": "payload",
        "msgPropertyType": "str",
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        "resultTypeType": "return",
        "multipleResult": false,
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        "setTopic": false,
        "outputs": 1,
        "x": 856.2222671508789,
        "y": 253.0000705718994,
        "wires": [
            [
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        "id": "4e77caafce2b081f",
        "type": "global-config",
        "env": [],
        "modules": {
            "node-red-contrib-buffer-parser": "3.2.2"
        }
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]
2

Firstly, some actual data and the value you expect it to represent would be helpful.

Use the Copy Value button that appears when you hover over an item in the debug panel. And when pasting the data to your reply, wrap it in triple ``` backticks to preserve formatting.

  1. Please provide the data coming out of OPC
    2. Include what you expect this to actually be (e.g. pressure 1740, out1 ON, out2 OFF, diag Normal)
  2. Please provide the code from the function node "Convert to array for parser"
3

Respected Steve Sir,

Are you able to import my flow ?
I think I forgot backticks in previous response:

I am expecting the pressure value to be "0.58 Mpas".
(Out1-On) (Out2-On) (diag- Normal)

Function code in the "Convert array to Parser" I converted the output of OPC in the array format as I was getting output in Object form from OPC client.
Code is as mentioned below:

Function Node code
Function Node code968×827 17 KB

var array = Object.values(msg.payload); // Converting the object data type to array
msg.payload = array;
node.status({ fill: "red", shape: "ring", text:msg.payload });
return msg;

{"_msgid":"efd5d465beb20ba3","payload":{"0":0,"1":0,"2":0,"3":0,"4":0,"5":0,"6":0,"7":0,"8":0,"9":0,"10":103,"11":235,"12":0,"13":0,"14":0,"15":0},"topic":"ns=2;s=type=0&circ=0&slavenr=1.ProcessData.InputData","datatype":"Byte","browseName":"","statusCode":{"value":0},"serverTimestamp":"2025-09-29T07:17:53.900Z","sourceTimestamp":"2025-09-29T07:17:53.900Z"}

I am attaching the whole flow again as I did not use backticks.
Please see the whole flow:

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        "id": "cdfc96937a19ffb6",
        "type": "function",
        "z": "d46daf54501e291d",
        "name": "Convert to array for \"PARSER\"",
        "func": "var array = Object.values(msg.payload); // Converting the object data type to array\nmsg.payload = array;\nnode.status({ fill: \"red\", shape: \"ring\", text:msg.payload });\nreturn msg;",
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        "timeout": 0,
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        "finalize": "",
        "libs": [],
        "x": 610.8664093017578,
        "y": 251.00010108947754,
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4

Like last time, you have only exported 1 node.
To export a flow, you need to select all nodes you want in the export.

PS, dont bother exporting your FULL flow as I dont have your OPC data source (or OPC nodes installed) - instead, you could simulate the OPC data by capturing it (Debug->copy value) and adding to your flow using an inject + function node.

5

It is very unlikely the data in those 13 bits are formatted for the the unit MPa - io-link data is often binary and requires conversion. Do you have this information?

6

Ok Steve Sir noted.

Did you get the data that is required to understand my problem or where I am making mistake ?

I am giving offset = 10 as the data is on byte 10, using Int16(le) as the data from SMC vendor is coming in Little endian.

10.0 Out1
10.1 Out2
10.2 Diag
10.3 to 11.7 Process data for pressure sensor

PD SMC Vendor
PD SMC Vendor1280×626 152 KB

8

Yes sir I was talking to you about the end result in unit of "Mpa" IO link is digital so i will get digital or binary values.

Did you also see in parser in "Scaling" I used ">>>3" to shift to right just by three bits to remove the unwanted data.
Then I multiplied the output of parser with 0.000250
Then offset of -0.25 to get desired results.

Which i am getting the correct response.

It is just that when I changed the port1 to port 3 Its not working so there is something that I am missing in offset or fundamentals wrong.

Sir please see attachment that I was getting desired response in yellow when I configured at port1.

Pressure Sensor Values
Pressure Sensor Values1536×864 259 KB

9

So when you change to another port on IOLink, the data is in a different position. You had an offset of 10. Which means you were reading from byte 10 (WORD 5 or in your case, since you converted to an array, this is index5 in the array)

image
image642×253 52.6 KB

image
image1514×260 24.8 KB

As per Buffer Parser built in help:

A node that converts an array of integer (Int16) or a buffer in to an object of values based on the specification provided

The problem.

Your debug node shows data output by OPCUA is a Uint8Array (i.e. an array of bytes) - that means after your function "Convert to Array" you are sending an array of 8 bit values to the buffer parser. It should be an array of 16 bit values OR a Buffer of bytes.

The correct way.

  1. Convert the payload to a buffer
    image
    image312×150 3.8 KB

    image
    image811×149 10.5 KB
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Also, the doc states "Unsigned 13 bit" you had selected int16le

10

Respected Steve Sir,

I don't understand it.
Ok I got the point that when I convert it to array each element is of 16 bit rather then 8 bit but then how do i get correct response. ?

After converting it to buffer as you said for the same pressure reading I am getting different values.

What data type should I keep ?
I kept int16(le) as the data is coming in little endian from SMC.
I want to read byte 10 and byte 11 so int16.

Now I am getting more and more confused.

After Bufpng
After Bufpng1919×973 131 KB

how do i remove Byte10.0, byte 10.1 and byte 10.2 which is not relevant to me ?
I use >>>3 in scaling. is it correct ?

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    {
        "id": "7f1a8165644967b8",
        "type": "function",
        "z": "d46daf54501e291d",
        "name": "Convert to Buffer",
        "func": "msg.payload = Buffer.from(msg.payload);\nnode.status({ fill: \"red\", shape: \"ring\", text: [...msg.payload.values()].toString() });\nreturn msg;",
        "outputs": 1,
        "timeout": 0,
        "noerr": 0,
        "initialize": "",
        "finalize": "",
        "libs": [],
        "x": 682.1111297607422,
        "y": 264.2222366333008,
        "wires": [
            [
                "166bcf76d196177e"
            ]
        ]
    },
    {
        "id": "13b6ec4236cb4585",
        "type": "function",
        "z": "d46daf54501e291d",
        "name": "Convert to Buffer",
        "func": "msg.payload = Buffer.from(msg.payload);\nnode.status({ fill: \"red\", shape: \"ring\", text: [...msg.payload.values()].toString() });\nreturn msg;",
        "outputs": 1,
        "timeout": 0,
        "noerr": 0,
        "initialize": "",
        "finalize": "",
        "libs": [],
        "x": 702.1111221313477,
        "y": 588.2222394943237,
        "wires": [
            [
                "d5b6cef6647867bf"
            ]
        ]
    },
    {
        "id": "6c8927a5ed0034ab",
        "type": "mqtt-broker",
        "name": "",
        "broker": "192.168.1.200",
        "port": 1883,
        "clientid": "",
        "autoConnect": true,
        "usetls": false,
        "protocolVersion": 4,
        "keepalive": 60,
        "cleansession": true,
        "autoUnsubscribe": true,
        "birthTopic": "",
        "birthQos": "0",
        "birthRetain": "false",
        "birthPayload": "",
        "birthMsg": {},
        "closeTopic": "",
        "closeQos": "0",
        "closeRetain": "false",
        "closePayload": "",
        "closeMsg": {},
        "willTopic": "",
        "willQos": "0",
        "willRetain": "false",
        "willPayload": "",
        "willMsg": {},
        "userProps": "",
        "sessionExpiry": ""
    },
    {
        "id": "d5876577da118764",
        "type": "OpcUa-Endpoint",
        "endpoint": "opc.tcp://192.168.10.40:4840",
        "secpol": "Basic256",
        "secmode": "Sign",
        "none": false,
        "login": true,
        "usercert": false,
        "usercertificate": "",
        "userprivatekey": ""
    },
    {
        "id": "d95953a57a8ab1a5",
        "type": "global-config",
        "env": [],
        "modules": {
            "node-red-contrib-opcua": "0.2.340",
            "node-red-contrib-buffer-parser": "3.2.2"
        }
    }
]
11

Your flow:

image
image1153×707 76 KB

12

When you provide sample data PLEASE provide what value you expect these to be.

image
image386×484 50.9 KB

13

Does this look right?

image
image1501×433 32.1 KB

[{"id":"cf58c22509393b43","type":"function","z":"307abce67fc6d2da","name":"OPC Data Uint8Array \\n 0,0,0,0,0,0,0,0,0,0,103,91,0,0,0,0","func":"msg.payload = new Uint8Array([0,0,0,0,0,0,0,0,0,0,103,91,0,0,0,0])\nreturn msg;","outputs":1,"timeout":0,"noerr":0,"initialize":"","finalize":"","libs":[],"x":360,"y":320,"wires":[["e7879cd9668d6c12","2d9aea3bf657076d"]]},{"id":"8238f2a20d99d533","type":"inject","z":"307abce67fc6d2da","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"","payloadType":"date","x":175,"y":320,"wires":[["cf58c22509393b43"]],"l":false},{"id":"e7879cd9668d6c12","type":"debug","z":"307abce67fc6d2da","name":"Output of OPC client","active":false,"tosidebar":true,"console":false,"tostatus":true,"complete":"true","targetType":"full","statusVal":"payload","statusType":"auto","x":640,"y":360,"wires":[]},{"id":"2d9aea3bf657076d","type":"function","z":"307abce67fc6d2da","name":"Convert to Buffer","func":"msg.payload = Buffer.from(msg.payload);\nnode.status({ fill: \"red\", shape: \"ring\", text: [...msg.payload.values()].toString() });\nreturn msg;","outputs":1,"timeout":0,"noerr":0,"initialize":"","finalize":"","libs":[],"x":630,"y":280,"wires":[["e946850af2adadcb"]]},{"id":"e946850af2adadcb","type":"buffer-parser","z":"307abce67fc6d2da","name":"","data":"payload","dataType":"msg","specification":"spec","specificationType":"ui","items":[{"type":"uint16be","name":"pressure","offset":10,"length":1,"offsetbit":0,"scale":">> 3","mask":""},{"type":"bool","name":"out1","offset":10,"length":1,"offsetbit":0,"scale":">> 3","mask":""},{"type":"bool","name":"out2","offset":10,"length":1,"offsetbit":1,"scale":">> 3","mask":""},{"type":"bool","name":"diagnostics","offset":10,"length":1,"offsetbit":2,"scale":">> 3","mask":""}],"swap1":"swap16","swap2":"","swap3":"","swap1Type":"swap","swap2Type":"swap","swap3Type":"swap","msgProperty":"payload","msgPropertyType":"str","resultType":"keyvalue","resultTypeType":"return","multipleResult":false,"fanOutMultipleResult":false,"setTopic":false,"outputs":1,"x":850,"y":280,"wires":[["1d4c22374437109c","3459fb8e3c35b3d2"]]},{"id":"1d4c22374437109c","type":"function","z":"307abce67fc6d2da","name":"Scaling with 0.00025","func":"const original = { ...msg.payload}\nmsg.payload.pressure = ((msg.payload.pressure * 0.00025) - 0.25)\nmsg.payload.pressureUnit = 'Mpa'\nmsg.payload.pressureFormula = '(v * 0.00025) - 0.25'\nmsg.payload.out1 = msg.payload.out1 ? 1 : 0\nmsg.payload.out2 = msg.payload.out1 ? 1 : 0\nmsg.payload.diagnostics = msg.payload.diagnostics ? \"Abnormal\" : \"Normal\"\nmsg.payload._raw = original\nnode.status({ fill: \"red\", shape: \"ring\", text: msg.payload.pressure.toFixed(3) });\nreturn msg;","outputs":1,"timeout":0,"noerr":0,"initialize":"","finalize":"","libs":[],"x":1080,"y":280,"wires":[["19f96a99c9927d6c"]]},{"id":"3459fb8e3c35b3d2","type":"debug","z":"307abce67fc6d2da","name":"Output of Parser","active":true,"tosidebar":true,"console":false,"tostatus":true,"complete":"payload","targetType":"msg","statusVal":"payload","statusType":"auto","x":1060,"y":340,"wires":[]},{"id":"19f96a99c9927d6c","type":"debug","z":"307abce67fc6d2da","name":"Final pressure Value","active":true,"tosidebar":true,"console":false,"tostatus":true,"complete":"payload","targetType":"msg","statusVal":"payload","statusType":"auto","x":1320,"y":280,"wires":[]}]

The important bits:

image
image803×471 19.1 KB

  • byte swap the data and use UINT BE
  • Shift the value to bit 0
14

Sir I have no idea what this values should be from sensor as this is converted by OPC Server.

See how i do in siemens PLC where I know what my RAW count is .

Siemens PLC for refernce
Siemens PLC for refernce1828×309 69.1 KB

15

No Steve Sir,
I copied your code and tried but it is incorrect.
I see pressure of 0.5 Mpa and with your code it is 1.0512 Mpa

16

As far as I can see it is correct.

image
image1525×408 39.1 KB

[{"id":"8238f2a20d99d533","type":"inject","z":"307abce67fc6d2da","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"","payloadType":"date","x":175,"y":320,"wires":[["cf58c22509393b43"]],"l":false},{"id":"e7879cd9668d6c12","type":"debug","z":"307abce67fc6d2da","name":"Output of OPC client","active":false,"tosidebar":true,"console":false,"tostatus":true,"complete":"true","targetType":"full","statusVal":"payload","statusType":"auto","x":640,"y":360,"wires":[]},{"id":"e946850af2adadcb","type":"buffer-parser","z":"307abce67fc6d2da","name":"","data":"payload","dataType":"msg","specification":"spec","specificationType":"ui","items":[{"type":"uint16be","name":"pressure","offset":10,"length":1,"offsetbit":0,"scale":">> 3","mask":""},{"type":"bool","name":"out1","offset":10,"length":1,"offsetbit":0,"scale":">> 3","mask":""},{"type":"bool","name":"out2","offset":10,"length":1,"offsetbit":1,"scale":">> 3","mask":""},{"type":"bool","name":"diagnostics","offset":10,"length":1,"offsetbit":2,"scale":">> 3","mask":""}],"swap1":"swap16","swap2":"","swap3":"","swap1Type":"swap","swap2Type":"swap","swap3Type":"swap","msgProperty":"payload","msgPropertyType":"str","resultType":"keyvalue","resultTypeType":"return","multipleResult":false,"fanOutMultipleResult":false,"setTopic":false,"outputs":1,"x":850,"y":280,"wires":[["1d4c22374437109c","3459fb8e3c35b3d2"]]},{"id":"1d4c22374437109c","type":"function","z":"307abce67fc6d2da","name":"Scaling with 0.00025","func":"const original = { ...msg.payload}\nmsg.payload.pressure = ((msg.payload.pressure * 0.00025) - 0.25)\nmsg.payload.pressureUnit = 'Mpa'\nmsg.payload.pressureFormula = '(v * 0.00025) - 0.25'\nmsg.payload.out1 = msg.payload.out1 ? 1 : 0\nmsg.payload.out2 = msg.payload.out1 ? 1 : 0\nmsg.payload.diagnostics = msg.payload.diagnostics ? \"Abnormal\" : \"Normal\"\nmsg.payload._raw = original\nnode.status({ fill: \"red\", shape: \"ring\", text: msg.payload.pressure.toFixed(3) });\nreturn msg;","outputs":1,"timeout":0,"noerr":0,"initialize":"","finalize":"","libs":[],"x":1080,"y":280,"wires":[["19f96a99c9927d6c"]]},{"id":"3459fb8e3c35b3d2","type":"debug","z":"307abce67fc6d2da","name":"Output of Parser","active":true,"tosidebar":true,"console":false,"tostatus":true,"complete":"payload","targetType":"msg","statusVal":"payload","statusType":"auto","x":1060,"y":340,"wires":[]},{"id":"19f96a99c9927d6c","type":"debug","z":"307abce67fc6d2da","name":"Final pressure Value","active":true,"tosidebar":true,"console":false,"tostatus":true,"complete":"payload","targetType":"msg","statusVal":"payload","statusType":"auto","x":1320,"y":280,"wires":[]},{"id":"2d9aea3bf657076d","type":"function","z":"307abce67fc6d2da","name":"Convert to Buffer","func":"msg.payload = Buffer.from(msg.payload);\nnode.status({ fill: \"red\", shape: \"ring\", text: [...msg.payload.values()].toString() });\nreturn msg;","outputs":1,"timeout":0,"noerr":0,"initialize":"","finalize":"","libs":[],"x":630,"y":280,"wires":[["e946850af2adadcb"]]},{"id":"cf58c22509393b43","type":"function","z":"307abce67fc6d2da","name":"OPC Data Uint8Array \\n 0,0,0,0,0,0,0,0,0,0,103,91,0,0,0,0","func":"msg.payload = new Uint8Array([0,0,0,0,0,0,0,0,0,0,103,91,0,0,0,0])\nreturn msg;","outputs":1,"timeout":0,"noerr":0,"initialize":"","finalize":"","libs":[],"x":360,"y":320,"wires":[["9558d92e59f5a64f"]]},{"id":"dc24d34e57670ec9","type":"inject","z":"307abce67fc6d2da","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"","payloadType":"date","x":175,"y":240,"wires":[["23da6c6f4ad10283"]],"l":false},{"id":"23da6c6f4ad10283","type":"buffer-maker","z":"307abce67fc6d2da","name":"faking Siemens PLC","specification":"spec","specificationType":"ui","items":[{"name":"item0","type":"uint16be","length":1,"dataType":"num","data":"0"},{"name":"item1","type":"int16be","length":1,"dataType":"num","data":"0"},{"name":"item2","type":"int16be","length":1,"dataType":"num","data":"0"},{"name":"item3","type":"int16be","length":1,"dataType":"num","data":"0"},{"name":"item4","type":"int16be","length":1,"dataType":"num","data":"0"},{"name":"item5","type":"uint32le","length":1,"dataType":"num","data":"26451"},{"name":"item7","type":"uint16be","length":1,"dataType":"num","data":"0"},{"name":"item8","type":"uint16be","length":1,"dataType":"num","data":"0"}],"swap1":"","swap2":"","swap3":"","swap1Type":"swap","swap2Type":"swap","swap3Type":"swap","msgProperty":"payload","msgPropertyType":"str","x":320,"y":240,"wires":[["9558d92e59f5a64f"]]},{"id":"9558d92e59f5a64f","type":"junction","z":"307abce67fc6d2da","x":520,"y":320,"wires":[["2d9aea3bf657076d","e7879cd9668d6c12"]]}]
17

Steve Sir,

This is 100 percent correct but how did you do this ? I am trying the same and not getting answer.
The raw count is same as SIEMENS and the value of pressure is also perfectly matching.

18

Steve Sir,

Thank you very much for your support.
I wasted lot of your time yesterday.
Sorry for that.
I appreciate that you took time out from your busy schedule to help me and all other node red members. Highly appreciated.

I started fresh in the morning today and used your concept of buffer and is very helpful and got all desired results.

But for today I still have doubt that yesterday why did you use UINT32(le) in "UI" configuration and not "UINT16(be)" ?

I also understood that you placed that value at item 5 because my data was on byte 10,
Each item is of 2 bytes so my data should be on item 5 or Index 5 of an array.
But confused why did you take datatype as "Uint32" and "little endian".

Thank you so much for your support.

WHy UINT32
WHy UINT321919×974 90.3 KB

1 Like
19

Final results of my project.

Thanks a lot.

I have also sent you a request on "LinkedIn" to connect.
Hoping for a positive response.

FInal results
FInal results1919×972 127 KB

1 Like