Modbus Protocol

Eric Hamilton

Updated: 10:58 AM 7/8/2025

MODBUS® is a registered trademark of Schneider Electric USA, Inc.

This information has been copied from the Modbus Web site modbus.org

Lammert Bies lammertbies.nl, has much useful information about this protocol and several others on his web site

  1. MODBUS/TCP Security, Protocol Specification v36_2021-07-30.pdf, 20 pages 12/11/2024 12:47 PM, MB-TCP-Security-v36_2021-07-30.pdf
  2. Modbus Application Protocol V1 1b3.pdf, 50 pages 12/11/2024 12:47 PM, Modbus_Application_Protocol_V1_1b3.pdf
  3. MODBUS APPLICATION PROTOCOL SPECIFICATION, V1.1b, 51 pages 05/20/2008 07:31 AM, Modbus_Application_Protocol_V1_1b.pdf
  4. Modbus Messaging Implementation Guide V1 0b.pdf, 46 pages 12/11/2024 12:48 PM, Modbus_Messaging_Implementation_Guide_V1_0b.pdf
  5. Modbus over serial line specification and implementation guide V1.02f, 44 page 12/11/2024 12:48 PM, Modbus_over_serial_line_V1_02.pdf
  6. Modicon, Modbus Protocol, Reference Guide, Rev J, 121 pages 12/11/2024 12:47 PM, PI_MBUS_300.pdf
  7. MODBUS MESSAGING ON TCP/IP IMPLEMENTATION GUIDE,V1.0b, 46 pages 03/31/2007 01:33 PM, MGuide.pdf
  8. MODBUS over Serial Line, Specification and Implementation Guide, V1.02, 44 pages 03/31/2007 01:33 PM, MSerial.pdf
  9. Object Messaging Specification for the MODBUS/TCP Protocol Vers1.1, 28 pages 12/11/2024 01:06 PM, Modbus Extensions