Hi, I have problems to convert float and 32b (signed/unsigned) registers to obtain a result able to be sent to MQTT broker. The modbus device is a semaphore/Servelec Tbox unit. I use node-red modbustcp Example: I have a float register with a value of 22.362 in it. I want to pass that value to my M…

In the Change nodes where you extract the individual parts add another row that Sets msg.topic To the/topic/for/this/value

[image] Steve-Mcl: I suspect when you update msg.payload in function 1 you are affecting the object before it's processed in the 2nd function. Assuming this is in a recent version of node-red ( @PPz which version is it?) then I don't think that should happen as node-red should automatically cl…

[image] Colin: node.warn() thank you both of you ( @Steve-Mcl ) for your kind help. My version is 1.0.3 the code of the function is : let pay = msg.payload; const buf = Buffer.allocUnsafe(4); // (4) is ok buf.writeUInt16BE(pay[0]); // high byte msg.payload = buf.readFloatBE(0); // 2 numb…

[image] PPz: about node.warn(), I'm affraid that I'm a real newbie about node-red Have you tried searching for it?

[image] Colin: node.warn() Yes, but when I inject node.warn(pay); I receive exactly the same array value [16818,58720] as the raw debug message Update: when I inject node.warn(buf), I obtain a splitted array like this one: [65,178,98,5], or [65,178,125,3], or [65,178,0,0] (variable). Ok, 1…

[image] PPz: let pay = msg.payload; const buf = Buffer.allocUnsafe(4); // (4) is ok buf.writeUInt16BE(pay[0]); // high byte msg.payload = buf.readFloatBE(0); You are allocating a buffer of length 4 bytes. Then you use writeUInt16BE to write to the first two bytes. You have not written an…

[image] Payload's number to two 16 bit register to be send via modbus General Hi ! U can use this code in function....after connect it to Modbus Flex Write function float32ToUint16(value) { var buffer = new ArrayBuffer(4); var intView = new Uint16Array(buffer); v…

tagging @Iqapps Thank you. I need to dig more about this and I will probably come come back later with this. For you, it's probably a piece of cake. Not that obvious for me (must read some doc. I usually learn while have a problem to solve). For the moment, I simplified my problem with my PLC (tha…

Here is little more information about how modbus handle 32 bit.... [image] How Real (Floating Point) and 32-bit Data is Encoded in Modbus RTU Messages Modbus Integration Solutions Chipkin has Modbus solutions for almost every situation. We are experts in Modbus R…

tagging @Colin thanks for the doc and the help. I discovered more and more and simplified a lot. Build on my plc a set of int16 registers. at first, I defined different polls, but the target plc was not happy of that (poll errors) Like in modbus devices, I set now 1 poll with successive address…

Mucho Perfecto ! And much faster too... [nore-red 1 poll multiple topics mqtt] [hubitat-mqtt-modbus]

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Newbie: convert modbus float [array] register to float value

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Iqapps 15 January 2020 10:39 11

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Newbie: convert modbus float [array] register to float value

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