Questions tagged [modbus]

Modbus is a simple protocol for serial communication between electronic devices.

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Reading MODBUS on ESP32

I'm working on a project for Smart Meter in this I'm reading MODBUS RS485 on ESP32 via MAX485 TTL To RS485 Overview : So, basic flow is, reading MODBUS as per MOSBUS Mapping list given by Smart Meter ...
Just doin Gods work's user avatar
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174 views

Modbus rtu server library which logs the requests

Kindly seek help. In my project I want to ‘fake’ a smart meter via Modbus rtu server for a solis inverter. Somehow the solis realizes that I am faking him, so I am wondering which Modbus rtu server ...
behn66's user avatar
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Arduino RS485 do I need MAX485?

I'm trying to connect sesnor that use RS485 (I'm almost sure that's modbus). The sensor has RX/TX and +/- wires. Do I still need a component between the RX/TX pin from the Arduino UNO and the sensor ...
Dafik's user avatar
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Modbus RS485 Decode the message received

I'm try to read some value from a soil NPK sensor using RS485 Modbus e Arduino uno. I menage to sent the request msg and I got the response but now i don't know how to read the response in order to ...
Damiano Miazzi's user avatar
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Trying to use an Arduino Uno to control two slaves with one master but its not working

I am trying to use following code but its not working. Need a help in this regard. #include <SimpleModbusMaster.h> #define baudrate 115200 #define timeout 2000 #define polling 500 #define ...
Ashish kumar's user avatar
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Using ModbusRTU.h, what would cause holding registers all read 0?

I'm working with a 32-Input Modbus RTU module using RS485. I'm trying to read/poll the inputs to check for ON(1) states. I have tested this module with Arduino UNO, Radzio! Modbus Master simulator, ...
Ashton's user avatar
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Cannot read values stored in bool* pointer [closed]

I'm trying to read values stored in a bool* pointer from a modbus coil call. I'm using modbus-esp8266 library. it's all ok with Input Registers and Holding Registers but i cannot read the result of a ...
MarioC's user avatar
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ESP8266 - MAX3485 Modbus not getting data

I'm trying to connect a modbus meter to a nodeMcu LoLin v3 I'm using a MAX3485 module to transfer the TTL to a RS485 connection. The modbus server has unitId 1, baud rate 9600 and no Parity This is ...
MarioC's user avatar
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Modbus rtu data decimal to float conversion

Hi,am trying to communicate with power-factor controller [Selec APFC 148-312] using modbus RTU,am following example sketch from modbusmaster library. am able to get the raw data from the instrument ...
Ragaven N's user avatar
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ARDUİNO MODBUS TCP CONNECTİON

I am trying to communicate with PC by using modbus TCP communicate. When I use this code I can't communicate. Dou you know guys what is the problem? My ethernet Module is working I know that because I ...
A Alptekin's user avatar
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2 answers
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When it comes to UART to RS485 communication, what is the difference between the 'MAX485' and the 'HW-0519' module?

I recently found this model with the ID 'HW-0519' on it. It can be found online (HW-0519 in Aliexpress) and is sold for the purpose of converting UART to RS485 communication using Arduino devices. The ...
C Vith's user avatar
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Which sensor bus best to use?

I am working on a project which requires a dozen VL53l0X I2C-TOF sensors to be polled by one master MCU over a few meters of cable. Thus, I decided to accompany each TOF by an Atmega8 acting as a ...
Daniel D.'s user avatar
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1 answer
1k views

Connect 12 V DC sensor to Arduino Uno using TTL RS485

I'm trying to connect an Arduino Uno with a BGT PM2510 sensor (which uses 7-12 V DC) by using a UART TTL to RS485 Two-way Converter. The only thing I wonder about is: can the sensor damage the MCU? ...
Redplane's user avatar
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Simple ModBus Master function 15

I have a simple setup with arduino Nano as slave and a arduino Mega as master Can anyone explain how the function 15 FORCE_MULTIPLE_COILS Works i have been running some test on this and cant figure ...
Eric V's user avatar
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Modbus TCP together with MQTT over same ethernet

I'm currently in a planning phase for a project. I want to read some sensor data over Modbus TCP, do some simple calculations on the Arduino and publish the results over MQTT. Which means I have 2 RJ-...
Jakube's user avatar
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Modbus TCP/IP using Arduino uno and ENC28J60 module

I have this project where I need a modbus tcp server that will host a series of sensor data for other modbus client devices to read. I use this Library by Andresoarmento This is the code i am using ...
Deadpool's user avatar
1 vote
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The Pfieffer Vacuum Protocol for RS485

i am working on a control Interface for serveral Components including turbo Pumps from the company Pfeiffer. The communication will be done according to the The Pfieffer Vacuum Protocol for RS485. ...
Fedi Chaarana's user avatar
1 vote
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261 views

ESP32-POE/ISO unstable after 10 days of power up

i have one ESP32-POE and ESP32-POE and i'm using the Olimex RS485 module to read a power meter that is placed near the ESP32 (5 meters of CAT5 cable - 9600 8N1). My device has this workflow (it's ...
SardoMan's user avatar
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2 answers
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Arduino Modbus Slave Library Needed

We are building a circuit based on ATMega328* that : Reads 32 current transducers, multiplexed into one Analog Input, Reads 12 voltage transducers, multiplexed into one Analog Input, Reads 6 ...
A.H. Shukry's user avatar
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ModbusMaster - Read 64 Bit integer

i'm using ModbusMaster library (Repo) to read from a device some registers. Many of them are float and i've no problem to read them using the following code: //for float conversation union { ...
SardoMan's user avatar
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Modbus programming

I have a Controllino Mega running a code that rotates a stepper one revolution CW, and one revoluction CCW. I need the program to run, just when a signal is received from an HMI that I have connected ...
Merkhav's user avatar
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Controllino Mega and Fatek HMI

I have a setup that controls the rotation of two stepper motor using Arduino UNO, HBS860H stepper drivers, 4X4 keypad and LCD screen. I have replaced the Arduino Uno by a Controllino Mega and it works ...
Merkhav's user avatar
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How can i read and write the data from a Delta plc-s series through Arduino UNO?

I am trying to communicate PLC with arduino through rs232 as well rs 485. But, I am not able to read and write data. I can observe the data in PLC through ladder logic but not in arduino. I am trying ...
Mohit Tripathi's user avatar
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1 answer
3k views

Controlling VFD with ModBus RTU via RS485 and Arduino

I am attempting to control a Folinn VFD (Manual: Manual) with an Arduino Uno via a MAX485 module such as this. Pins for MAX485: DI > D8 DE & RE > D10 RO > D11 VFD settings: F00.01 set to 2 ...
Jacob Rodda's user avatar
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can ModbusRtu.h library send data from slave to master using modbus(RS485) module?

i am using ModbusRtu.h library for modbus protocol. it works for sending data from master to slave but it can not send data from slave to master. master code: #include <ModbusRtu.h> #define ...
MD Golam Morsed's user avatar
1 vote
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71 views

I am interfacing Amonia Sensor RS485 output with Arduino Mega . not getting any response

I am interfacing Amonia Sensor RS485 output with Arduino Mega but not getting any response. i need to transmit {0x06, 0x03, 0x00, 0x00, 0x00, 0x04, 0x45, 0xBE}; frame to sensor then senor will send ...
Rahul Jathar's user avatar
-1 votes
1 answer
1k views

How to Use Function Code 6 Modbus RTU library

I'm trying to communicate with a temperature controller using Modbus RTU. I used this Arduino library. I was able to read PV(current temperature value) using below code. It uses Function code 4. I ...
user_fs10's user avatar
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Reading a simple sensor with Modbus RTU on Arduino Uno

I'm integrating a wind direction- and speed sensor with an Arduino. It communicates over RS485 Modbus RTU, which I don't have any experience with. The documentation is very short, and it just says: ...
Vincent Vega's user avatar
1 vote
1 answer
2k views

NodeMCU Modbus interfacing with Pressure Multi-Switch

I've been trying to interface between a NodeMCU and a Dotech DPX200 Pressure Multi-Switch over Modbus RS485 using a MAX485 Module for the past few weeks, going through nearly every Modbus post on this ...
Nikhil Nair's user avatar
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1 answer
4k views

Stack smashing protect failure ESP32 with Modbus RTU

I'm doing a project using an ESP32 TTGO with LoRa, the Max485 and a WELLPRO ADAM 8082 for Modbus communication. I'm trying to use the ESP32 as a master to and the ADAM as a slave. I'm also using Node-...
Biel's user avatar
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480 views

Arduino Mega with SIM800L running Modbus TCP/IP

I'm trying to set up an Arduino Mega with a SIM800L module and trying to get Modbus TCP running on said Mega. I've set Modbus TCP over wifi and serial before but I used libraries for those. The ...
Deniz Yörüten's user avatar
2 votes
0 answers
902 views

Unable to read data more than once via Modbus RTU

I'm a newbie to this forum so kindly excuse me for any errors. I'm using an Arduino Uno and Max485 (RS-485 to TTL) to communicate with a Power meter, but I'm able to receive the data from the Power ...
Sanj_Ard's user avatar
0 votes
2 answers
4k views

Arduino Uno & ESP32 communication using RS485

I am trying to establish a communication between Arduino Uno ( Master) and ESP32 (Slave) using RS485 protocol (using MAX485 module). I have successfully done this between two Arduino Unos. ...
KarmaCoding's user avatar
1 vote
0 answers
332 views

RS485 Arduino Communication Issue

Friends, I am trying to achieve half duplex communication between two Arduinos using RS485 Protocol. The hardware I am using is a MAX485 module and an Arduino Uno. I am using the SoftwareSerial ...
java bee's user avatar
1 vote
1 answer
728 views

Cannot read modbus data repetitively

I try to communicate with 2 RS485 sensors (pH and EC), but I have some troubles with my code. First, I tried to get data from just one: The function in charge of request sending: String GET_probe(...
Teddol's user avatar
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1 vote
0 answers
198 views

Arduino as Modbus RS485 slave using only 2 Digital pins

I want to use RX(0) and TX(1) Pins to make Arduino as an RS485 slave. To do this I am using MAX485 IC (Breakout board) https://datasheets.maximintegrated.com/en/ds/MAX1487-MAX491.pdf The problem here ...
Ohbhatt's user avatar
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2 votes
0 answers
2k views

Arduino Modbus slave error

I am trying to use Arduino as Modbus- RTU slave and Raspberry Pi as a Modbus master I have interfaced Max485 (RS485 to TTL converter) with Arduino and Rs485 to USB converter in Raspberry Pi, Initially,...
Sharath Mohan's user avatar
1 vote
0 answers
2k views

Arduino Modbus - Rtu slave with Raspberry pi using MAX-485

I am trying to use Arduino as Modbus- RTU slave and Raspberry Pi as a Modbus master I have interfaced Max485 (RS485 to TTL converter) with Arduino and Rs485 to USB converter in Raspberry Pi, Initially,...
Sharath Mohan's user avatar
0 votes
2 answers
2k views

Problem with modbus communication between two arduinos when writing more than 27 registers

I have the following problem: I want send 200 registers from a modbus master to a slave. Both are arduinos. I can't send more than 27 registers. When I send more i get the Errorcode 255 which means ...
ueberBrot's user avatar
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2 answers
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Modbus IP with Simply Modbus TCP

include SPI.h include Ethernet.h include Modbus.h include ModbusIP.h //Modbus Registers Offsets (0-9999) const int SENSOR_IREG = 100; //Used Pins const int sensorPin = A0; //ModbusIP object ModbusIP ...
Michael H.'s user avatar
0 votes
1 answer
2k views

Using Modbus-RTU with Arduino and temperature controller

I'm trying to connect with a 4 channel temperature controller using Arduino Modbus Library. This is a part of my temperature controller datasheet. It has register for read PV of each channel. I have ...
user_fs10's user avatar
  • 187
0 votes
1 answer
4k views

Using Modbus TCP server on Arduino

I have a scd30 sensor wired to an Arduino Uno. The scd30 works on the I2C protocol. I am able to read data live on the serial monitor on the Arduino IDE. I have an ethernet shield on my Arduino. I ...
user401708's user avatar
-1 votes
1 answer
2k views

Multiple #ifndef vs. single one #endif

My question is connected with the issue as linked: Is there any good working MODBUS TCP master library available for Arduino? An example of Modbus TCP master library as suggested in the post above. A ...
dskorupinski's user avatar
0 votes
1 answer
1k views

Arduino Modbus RTU VFD control

I need help with this code: /** * Modbus master example 1: * The purpose of this example is to query an array of data * from an external Modbus slave device. * The link media can be USB or RS232....
greekouzina's user avatar
1 vote
1 answer
14k views

How to make I2C work on RS485?

I'm trying to optimize the communication (minimize wires) on a project where I can control a motor and toggle some 230V devices by using RS485 and I2C. On this project, I'm using an Arduino (Mega) ...
Matthijs van Hest's user avatar
0 votes
1 answer
3k views

Arduino Modbus Master code to read data using arduino uno from EB meter

I am using DC energy meter as slave.When I am testing DC energy meter using Modbus tester tool,its showing value from 1 to 24 register.I am using my own atmega328P with on board RS485 as a master ...
user1811790's user avatar
4 votes
1 answer
25k views

Modbus RTU controller monitoring with arduino and RS485 module

I'm a medium user in Arduino. I baught a pHmeter controller with RS485 output (MODBUS RTU protocol). I want to get pH value read by the controller over RS485 module and Arduino. According the ...
Teddol's user avatar
  • 85
2 votes
2 answers
29k views

Arduino ModBus RTU master communication with Power Meter problem

i have an arduino UNO with RS485 module. I have made this connection: And i have an problem with communication of this module with power meter "InePro PRO-1Mod" (datasheet) over ModBus protocol. I ...
Vasekdvor's user avatar
1 vote
1 answer
395 views

Cannot obtain reading from meter (Modbus)

I have a system in which I am taking readings from a meter and processing it through an Arduino Nano. My code looks as follows: #include <SoftwareSerial.h> #define SerialControl 7 #define ...
Ashish K's user avatar
  • 141
0 votes
2 answers
977 views

float not a float

I am trying to read a SDM220 meter on my solar setup. I've been reading it using Modbus SCADA, so know it all works ok. But I want to read it with my Arduino Mega 256. My problem is that when I run ...
bres55's user avatar
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