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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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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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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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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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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Pelco D Library for Arduino

Does anyone know of any Pelco D libraries available for Arduino? I already have a PTZ joystick controlling 3 PTZ cameras, but I would like to add an Arduino 'intelligent' controller capable of ...
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74 views

Multi-drop RS485 device control v1.0 - why is limit for “TIME_BETWEEN_MESSAGES ”?

I am going to use Nick's rolling-master system library (http://www.gammon.com.au/forum/?id=11428) in my home project. For first experiments and testing, I have: - BAUD_RATE = 9600 - max adress = 2 (...
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1answer
376 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
542 views

Problem using ICSC (by majenkotech) in RS485 bus

I want to communicate with an RS485 Bus consisting of 5 Arduino Pro Minis as slaves and one Arduino Mega 2560 as Master. I found a great library for this. According to the documentation provided by ...
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1k views

rs485 and serial ISP

I made a couple of arduino mini pro and esp8266 pcbs with an rs485 transceiver just to find out that I forgot to think about in-system-programming: Assuming that I don't need to disable the ...
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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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Why ModBus RTU Master-Slave Dont Work

I have two mega arduino and want to them communicate with modbus rtu together, i use below link circuit for this : http://www.microcontroller-project.com/rs485-communication-between-arduino-mega-and-...
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Serial: What is different between Gammon's RS485 (blocking) and RS485 “non blocking” libraries?

The RS485 master-slave communication library on Nick Gammon's page http://www.gammon.com.au/Arduino/RS485_protocol.zip is working for me OK, but on the same hardware wiring is not working for the non-...
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107 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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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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135 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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338 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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179 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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71 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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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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322 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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2answers
993 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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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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87 views

RS-232 is a protocol or a cable?

RS-485 and RS-232 are a type of communication protocol or a type and cable? I studying these serial communication protocols and each place refers to the RS-232 / RS-485 in different ways. Some ...
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conexión rs232 ttl con max490

I can make a usb to ttl rs232 arrangement with max490 to be able to do full duplex communication between the PC and two arduino?
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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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93 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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SerialEvent with RS485 communication

I am not expert in Arduino programming but i can understand lit bit, while doing review i came across two sets of programs one using serialEvent and one with RS485 library, Now my problem is with ...
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49 views

PLC with Arduino UNO [duplicate]

In my current project I have to communicate with 10 different devices with PLC. PLC is the master. When input comes from PLC to a device, the Arduino controller through RS485, I want to check the ...
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862 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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1answer
278 views

Interfacing Gammon's RS485 with computer

I'm using the non-blocking RS485 Gammon's library for Arduino (as shown at http://www.gammon.com.au/forum/?id=11428) to handle the communication between some arduinos. Now I'm having trouble to add a ...
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1answer
2k views

Problem in RS485 Communication between Arduino and PC

I'm trying to sending and receiving data via RS485 communication. Interfacing Arduino and PC(laptop) using SN75176 RS485. I wrote a program to send a string "Hello" from arduino via Tx pin. My ...
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737 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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626 views

Communicate between NodeMCU ESP8266 gateway and multiple sensor nodes

What is the best wired way to communicate between multiple NodeMCU ESP8266 boards for home automation. Every room should get at least a light, temp, PIR and xx relay modules to switch things on and ...
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2answers
628 views

Transmit data to long distance (120m)

I want to transmit data from multiple sensors to an Arduino and distance would be approximately 120 meters. What protocol or configuration should I use? Actually I am trying to read values from 5 ...

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