Raspberry Pi Zero Modbus TCP/RTU Gateway using Node-RED

Simple way to communicate with Modbus RTU devices using Modbus TCP instead. The Raspberry Pi is acting as both a Modbus TCP slave and Modbus RTU master. The Node RED flow simply maps the slave commands over to the RTU addresses.

Parts List:
WAGO
750-8101 PFC100 Ethernet PLC
750-473 4ch AI Module
750-600 End Module
787-1602 24VDC 1A Power Supply
734-106 6 conductor MSC Mini Male
734-306 6 conductor MSC Mini Female
8002-025-000-007 WAGO USB Charging Station
289-175 RJ45 Interface Module
221-415 5-Position Lever Nuts
2002 Series Terminal Blocks

TECO L510 VFD
Baldor AC Motor 56J
Raspberry Pi Zero W
USB-RS485-WE USB to RS485 Adapter

[gr]

every time I forget how to do this communication, this video makes it clear to me. thanks from Spain

[galigadu]

Awesome video Kurt..I have been using Pi3 for my projects. I just ordered a zero. I will replace my Pi3 with zero.

[WillZotti]

Can you provide a link to the video you reference in the video for setting up the RPi? There is no link in the video, at least one that I have been able to click, and I haven't been able to find the video you are referencing. Thank you.

[powermate]

Thanks Kurt for a great vid. I have just bought a altivar 12 vsd. It has a rj45 connector with labels D1 and D2. My USB/RS485 adapter has A and B.. Would you know the correct connection for this. Thanks in advance Bradley Mohr..

[ofir]

Hi Kurt, i have some questions please:


i taking advantage the "corona times" to do some project with rpi and automation plc's(thats whare i come from(plc))
it this project i choose to use NODE-RED, and the rpi to create a very chip web based telemetry system (like you did in the video controlling modbus slave devices)


1. should i start learning java script before using node-red ?,


2. does people who are familiar with JS or node.js have some advantage ? by means ...it will be easy to them to use node-red ?


3. should i master LINUX OS before i go into programming the pi ? or just "go with the flow and ask google "how to" whanever i come across some problems ?

[alexszilagyi]

Great video! I have a question about a ModBus 485 over RTU. Do you know what might be: reading values from the device using ModScan54 works as expected but using node-red packages getting different value. Have you been in such a situation?

[lmarkrol]

Do you have a written tutorial? Thanks in advance

[sharadpatle]

Modbus TCP does not connect back when the connection is broken, how to solve this

[Thewonder]

Hi Kurt. Thanks for the videos. All very interesting. Just wondering, is there a way of controlling (reading and writing) an inverter with Modbus RTU via RS485 with node red, raspberry pi and a usb converter. All I see is tutorials using TCP rather than RTU?

[harleylovitos]

Hi sir, how are you? Where did you get the holding register? also how to connect using TCP with TECO VFD F510?

[mrusmanishtiaq]

Hi, Thanks for you fruitful video. Is it possible to directly connect modbus rtu frequency converter with raspberry pi?

[serhioromano]

It is not actually a TCP gateway but rather RS485-Etherner converter. For gateway I understand that you can connect few serial interface devices and convert it to single Ethernet.

Is there a way to connect for example 10 VFDs and control each one separately?

[Master_Teco]

Hi, thanks for your videos are very good, some expriencia with modbus tcp and plc zelio? greetings from Chile

[WagoKurt]

[{"id":"bdc4476f.b8ea08", "type":"modbus-server", "z":"c1481282.fa736", "name":"", "logEnabled":false, "serverPort":10502, "responseDelay":100, "delayUnit":"ms", "coilsBufferSize":1024, "holdingBufferSize":"4", "inputBufferSize":1024, "x":303, "y":114.5, "wires":[["2cb93c43.f66474", "4b3e36bd.2cbec8"], [], []], "outputLabels":["Jesse", "Frequency", ""]}, {"id":"efc51d9f.581fb", "type":"inject", "z":"c1481282.fa736", "name":"", "topic":"", "payload":"", "payloadType":"date", "repeat":"1", "crontab":"", "once":false, "x":123, "y":114, "wires":[["bdc4476f.b8ea08"]]}, {"id":"ab2fa413.486158", "type":"modbus-write", "z":"c1481282.fa736", "name":"Start", "showStatusActivities":false, "showErrors":false, "unitid":"1", "dataType":"HoldingRegister", "adr":"9473", "quantity":"1", "server":"ee4c917a.bb25d", "x":670, "y":80, "wires":[[], []]}, {"id":"2cb93c43.f66474", "type":"function", "z":"c1481282.fa736", "name":"Gateway", "func":"// Control\nvar low_byte = msg.payload[0];\nlow_byte = low_byte << 8;\nvar high_byte = msg.payload[1];\nvar x = low_byte + high_byte; \nvar msg1 = {payload: x};\n\n// Speed Ref\nlow_byte = msg.payload[2];\nlow_byte = low_byte << 8;\nhigh_byte = msg.payload[3];\nvar x = low_byte + high_byte;\nvar msg2 = {payload: x};\n\nreturn [msg1, msg2];\n", "outputs":"2", "noerr":0, "x":493, "y":102, "wires":[["ab2fa413.486158", "d011f589.5da148"], ["1239a31.5f9f85d", "669840d9.3c792"]]}, {"id":"1239a31.5f9f85d", "type":"modbus-write", "z":"c1481282.fa736", "name":"Freq", "showStatusActivities":false, "showErrors":false, "unitid":"1", "dataType":"HoldingRegister", "adr":"9474", "quantity":"1", "server":"ee4c917a.bb25d", "x":670, "y":140, "wires":[[], []]}, {"id":"4b3e36bd.2cbec8", "type":"debug", "z":"c1481282.fa736", "name":"", "active":false, "console":"false", "complete":"false", "x":490, "y":240, "wires":[]}, {"id":"669840d9.3c792", "type":"debug", "z":"c1481282.fa736", "name":"", "active":false, "console":"false", "complete":"false", "x":670, "y":200, "wires":[]}, {"id":"d011f589.5da148", "type":"debug", "z":"c1481282.fa736", "name":"", "active":false, "console":"false", "complete":"false", "x":670, "y":20, "wires":[]}, {"id":"ee4c917a.bb25d", "type":"modbus-client", "z":"", "name":"", "clienttype":"simpleser", "bufferCommands":true, "stateLogEnabled":false, "tcpHost":"127.0.0.1", "tcpPort":"502", "tcpType":"DEFAULT", "serialPort":"/dev/ttyUSB0", "serialType":"RTU-BUFFERD", "serialBaudrate":"9600", "serialDatabits":"8", "serialStopbits":"1", "serialParity":"none", "serialConnectionDelay":"100", "unit_id":1, "commandDelay":1, "clientTimeout":1000, "reconnectTimeout":2000}]