Here’s what more than 2,500 business decision-makers around the world say.Download the report
...with the Facility Hero app in hand! Discover how you can optimize your maintenance efforts today.Learn more
Access tailored services, 24/7 self-service and expert help. Anywhere, anytime, any project.Discover now
Everything you need to know about our IoT technology backbone.Learn more
Explore our global offerings or select your country from one of our five regions.Global
Découvrez nos offres globales ou sélectionnez votre pays dans l’une de nos cinq régions.
ModbusTCP is a connection oriented TCP protocol. The Acknowledgement TCP segment value includes the last received TCP segment value plus the number of bytes in the received ModbusTCP message. This way, the Master knows that the message was received intact.
If a Master's current TCP segment number is 100, and it sends a 14 byte ModbusTCP request, it expects to see a TCP Acknowledgement from that slave to be 114. If it is any other value, the slave did not receive the proper message. This should trigger an retransmission from the Master for a duplicate request.