Issues

• Modbus RTU on Opta needs RS485.setDelays() — please document and/or expose a passthrough

  topic: codetopic: documentationtype: enhancement
  arduino-libraries/ArduinoModbus#179 · Filter by author dorkmo opened on Apr 23, 2026
  1

• Error in API description for Modbus Server - write to hold register

  topic: documentationtype: imperfection
  arduino-libraries/ArduinoModbus#167 · Filter by author Sonnengruesser opened on Jul 10, 2025
  2

  

• How do you know which hardware serial port ModbusClient uses (e.g., Serial3 on STM32Duino)?

  arduino-libraries/ArduinoModbus#162 · Filter by author SeppeBudenaers opened on Apr 8, 2025
  1

• Endian type should be honored

  arduino-libraries/ArduinoModbus#161 · Filter by author bohnelang opened on Feb 28, 2025

• Library only working for 1 simultaneous Server on RP2040 using earlephilhower's arduino-pico platform

  type: imperfection
  arduino-libraries/ArduinoModbus#155 · Filter by author pomplesiegel opened on Aug 26, 2024
  3

• Timeout is blocking from reading input registers when using multiple slaves.

  type: imperfection
  arduino-libraries/ArduinoModbus#153 · Filter by author gramcracker opened on Jun 28, 2024

• ModbusClient.requestFrom() crashes Finder Opta if id > 247

  topic: codetype: imperfection
  arduino-libraries/ArduinoModbus#151 · Filter by author gareddustephane opened on May 14, 2024

• Modbus TCP Master AND Modbus RTU master - At the same time ?

  arduino-libraries/ArduinoModbus#149 · Filter by author ALIP-0 opened on Mar 27, 2024

• Does this library support Modbus TCP Security?

  type: enhancement
  arduino-libraries/ArduinoModbus#140 · Filter by author rafaelkai opened on Feb 14, 2024

• Programming issue? timeout without delay within the code

  type: imperfection
  arduino-libraries/ArduinoModbus#139 · Filter by author realKamillo opened on Jan 31, 2024
  2

• Add support for Modbus RTU over UDP

  topic: codetype: enhancement
  arduino-libraries/ArduinoModbus#137 · Filter by author zsoltyfm opened on Jan 16, 2024
  2

• Race condition: ModbusRTUServer.begin() sometimes quietly rejects config

  topic: codetype: imperfection
  arduino-libraries/ArduinoModbus#135 · Filter by author pomplesiegel opened on Dec 26, 2023

• Not able to decode ModbusTCPServer.Poll(); function to get the Function code for read or write Operation.

  type: imperfection
  arduino-libraries/ArduinoModbus#129 · Filter by author prakashvenugopal2014 opened on Nov 4, 2023

• Larger reads sometimes time out at slower baud rates on RP2040

  type: imperfection
  arduino-libraries/ArduinoModbus#125 · Filter by author pomplesiegel opened on Oct 8, 2023
  10

• Question about directly accessing holding register data array via union

  topic: documentationtype: enhancement
  arduino-libraries/ArduinoModbus#124 · Filter by author kurt-klingbeil opened on Sep 29, 2023

• Modbus RTU over TCP Support for Arduino Opta

  topic: codetype: enhancement
  arduino-libraries/ArduinoModbus#123 · Filter by author wicopretorius opened on Sep 22, 2023
  1

• Documentation of return values in ModbusServer.h and Arduino Reference does not match source code

  topic: documentationtype: imperfection
  arduino-libraries/ArduinoModbus#120 · Filter by author smacinnes opened on Aug 16, 2023

• Add support for UNO R4 WiFi board

  topic: codetype: enhancement
  arduino-libraries/ArduinoModbus#119 · Filter by author karl3200 opened on Jul 31, 2023
  2

• Broadcast transmission blocks for TIMEOUT ms

  topic: codetype: imperfection
  arduino-libraries/ArduinoModbus#117 · Filter by author bobemoe opened on Jul 28, 2023

• Multiple clients to one modbus TCP server

  arduino-libraries/ArduinoModbus#113 · Filter by author DriesVandb opened on Apr 6, 2023
  1

• RP2040: RX works, but always times out

  topic: codetype: enhancement
  arduino-libraries/ArduinoModbus#111 · Filter by author pomplesiegel opened on Mar 14, 2023
  12

• Use rtos::ThisThread::sleep_for as delay in _sleep_response_timeout() for Mbed OS boards

  topic: codetype: enhancement
  arduino-libraries/ArduinoModbus#107 · Filter by author salasidis opened on Jan 7, 2023

• Possible to add multiple blocks of holding registers?

  arduino-libraries/ArduinoModbus#102 · Filter by author nikstp opened on Oct 17, 2022
  2

• Change Serial port?

  topic: codetype: enhancement
  arduino-libraries/ArduinoModbus#99 · Filter by author RobWPink opened on Sep 5, 2022
  4

• Add warning to docs re: client assertion of DTR causing board reset

  topic: documentationtype: enhancement
  arduino-libraries/ArduinoModbus#98 · Filter by author c0d3rx opened on Jul 23, 2022