Questions tagged [rs485]

also known as ANSI/TIA/EIA-485, TIA/EIA-485, EIA-485 or RS-485, is a standard defining the electrical characteristics of drivers and receivers for use in balanced digital multipoint systems. The standard is published by the Telecommunications Industry Association/Electronic Industries Alliance (TIA/EIA).

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197 views

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 ...
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1answer
288 views

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 ...
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0answers
59 views

Arduino modbus program error

I was trying to extract data from a multi-function meter with RS485 connectivity and I am using Arduino as master, Arduino Uno and multi-function meter are connected via MAX485 module. I have tried ...
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1answer
357 views

Connect 12v DC sensor to Arduino UNO using TTL RS485

I'm trying to connect Arduino Uno with BGT PM2510 sensor (which uses 7-12V DC) by using UART TTL to RS485 Two-way Converter. The only thing I wonder is can the sensor damage the MCU ? According to the ...
2
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1answer
137 views

RS-485 Serial communication problem with arduino

I use 485 modules to transmit data serially from one arduino uno to another uno. If I connect the 2 arduino boards directly without using the rs485 module, the data is sent and received without a ...
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2answers
156 views

Read Internal Registers of RS485

I am trying to interface sele EM2M, I am using Arduino Mega with RS 485 module. I want to read the internal registers I am using ModbusMaster library. The data which I want to receive is in the ...
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2answers
114 views

Building RS485 serial to USB adapter with digispark

Is it possible to build an serial-adapter with digispark board? Like: Embedded System with 2-wire RS-485 Port connect to my digispark board. Digispark Board is connected via USB to my Computer (...
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1answer
185 views

How to count number of bytes appearing in the Arduino serial?

I need to count the number of bytes appearing in the serial (UART bus) bus, how to count bytes in Arduino with Arduino Serial functions? is this possible? Application - RS485 communication with ...
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40 views

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. ...
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2answers
2k views

read data from controller via RS485 Modbus rtu Arduino

I have a device with an rs485 port from which I would like to read the ph value. Below is the connection with the RS485 adapter. I tried to read the data with this code but doesn't work: #include ...
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1answer
140 views

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 ...
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720 views

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 ...
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1answer
1k 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 ...
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189 views

Arduino RS485 communication protocol - minimising overheads and best practice

I'm building a single master multiple slave RS485 network for remote sensors on test equipment. I have the hardware built and working, and I can do a Serial.print on the master and have the slaves ...
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4k views

NodeMcu Communication to RS485 Device using TTL to RS485 converter

Good day everyone,        I am facing a problem when trying to use nodemcu (Nodemcu ESP8266 Lolin V3) to communicate with an RS485 device. I sent an enquiry ...
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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 ...
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1answer
105 views

Unreliable communication with low baudrate on Leonardo

I am using an Arduino Leonardo (more precisely this product), to communicate with servo-motors) using RS485. Everything works fine as long as I don't go below a baud rate or 115200bps. If I go below, ...
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54 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 ...
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1answer
2k views

ESP32 Hardware Serial Flow control and full espressif/arduino-esp32 support

I have a similar issue. I want to use the ESP32 with RS485. I have used the Arduino and this works well assigning pins, but it seems not to allow full use of the UART. I see the new uarts in the ...
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2answers
897 views

RS485 communication problem

I'm trying to achieve RS485 communication between Arduino Mega and Arduino UNO as specified in following link: https://www.engineersgarage.com/arduino/rs485-communication-between-arduino-mega-and-...
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1answer
164 views

Serial Module Echoing a `0x00`

I am having a problem with a MAXIM Serial module (Config A) with a simple repeating code from COM port. When sending a character (k:0x6b) I receive a (0x00) echo. Without the module and just ...
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2answers
3k views

Arduino UNO and RS485 Communication Problem

I am learning Arduino, a beginner in programming. I want to use Arduino UNO to connect a wind direction sensor RS485. The problem is the output in the serial monitor, the return data from the wind ...
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1answer
373 views

NodeMCU: Wiegand not working for one device, while working for another

I'm using a NodeMCU, and a working code for reading Wiegand data, with this library. I managed to successfully read the Wiegand signal from this device. However, I also have this new AR-721H device, ...
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1answer
210 views

one Arduino with RS485 and Ethernet shields: does this work?

I'm planning to wire a few Arduinos together via RS485, and have one of them act as a hub that collects information from the others and presents it via http on an Ethernet connection. For instance ...
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0answers
375 views

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: ...
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1answer
75 views

Serial Enable Maxim RS485 Pin

If I want to use a MAXIM 485 for a RS485 communication, is there any option to include the Control DE and RE' pin in a natural manner in the code, instead changing the control pin everytime I made a ...
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2answers
2k views

Arduino RS485 shield to RS485 temperature & humidity sensor

I’m try to get data from rs485 is not work please advise to me. 1. Try to connect PC usb485 to DY-MD02 is work. Send command “AUTO” or “READ” 2. Try to Arduino rs485 shield to DY-MD02 is not ...
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1answer
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 ...
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1answer
4k views

Connecting multiple RS485 together

I am trying to build communication across multiple Arduino using RS485. When i am trying to connect 3 Arudino nano together using breadboard my code doesn't reach slave where as if i just if i do ...
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1answer
350 views

Arduino Hardware serial pins with RS485

I tried asking a question in my earlier post - SerialEvent with RS485 communication it helped me understand Hardware serial and Software serial but i had few more questions for which i started this ...
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0answers
613 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 ...
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2answers
3k 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. ...
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0answers
276 views

RS485 Serial Communication not working with Arduino

I am trying to control 2 devices with my arduino using RS485 communication. Basically switch on device 1 for 5 seconds when I send 'g' to the master. And switch on device 2 for e3 seconds when I send ...
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0answers
273 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 ...
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1answer
475 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(...
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1answer
929 views

Electric meter with Arduino and RS485 module

I'm a Arduino newbie. I have an Electric meter with an RS485 output. I want to get the MeterID value over the RS485 module and the Arduino. I just have document from manufacturer. Sent by computer : ...
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2answers
15k views

Arduino master/slave communication using RS485

I am using Arduino Uno as a Master Device and 3 Arduino Unos as slave devices. I am sending data from each slave to master after every 3 seconds continuously, and is going to execute further logic ...
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0answers
360 views

RS485 Wrong Results in Serial Monitor(Controllino) - Right Results with Logic Analyzer

After searching the internet and trying different examples, I always get the same wrong response in the serial monitor. Picture 1 shows the wrong results. At first i thought it was decimal and I just ...
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0answers
129 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 ...
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1k views

sending data with rs485

I need to read acceleration data with ADXL335 using ARDUINO MICRO (or NANO) and send this data with RS485 module to another RS485 module connected to an ARDUINO UNO (300m between RS485 modules). ...
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0answers
773 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,...
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0answers
1k 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,...
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2answers
1k 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 ...
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1answer
1k 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 ...
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1answer
377 views

Trying to power 100 Arduino's from single power line [closed]

I'm trying to power up to 100 Arduinos that will be spread across a 25m wall using a single power line. The idea is each Arduino will have a few a few buttons, leds & an oled screen and will all ...
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2answers
445 views

Arduino network with minimum wiring

For a parking management system I am going to create an Arduino network. An Arduino with an ultrasonic sensor will be placed above each parking space. If car is parked at specific location Arduino ...
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3answers
353 views

DMX on the Arduino without additional driver chip

I recently saw this video where the creator controlled a DMX light via the Arduino. There he used the pins 3 and 4 for the data on the Arduino Duemilanove. As DMX library he used DmxSimple. Based on ...
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1answer
8k 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) ...
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1answer
1k views

Arduino Mega RS485

I am following the instructions from this page to set up RS485 communication between two Arduinos. https://arduino-info.wikispaces.com/SoftwareSerialRS485Example My wiring varies slightly from the ...
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1answer
22k 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 ...