Modbus TCP is a communication protocol supported in EasyBuilder Pro that allows an HMI to exchange data with PLCs and other devices over an Ethernet network. It uses standard TCP/IP communication, enabling devices to connect using IP addresses and communicate across local or routed networks.
In EasyBuilder Pro, Modbus TCP is implemented through the device configuration, where the HMI is set up to communicate with a controller using the Modbus TCP driver. The HMI typically acts as a client (master), sending requests to a Modbus TCP server (slave) such as a PLC, and reading or writing data to defined register addresses.
Data exchange is based on standard Modbus addressing, allowing the HMI to access different types of data in the connected device:
- Coils and discrete inputs for bit-level data
- Registers for word-level data (read/write or read-only depending on type)
From the Maple Systems perspective, Modbus TCP is one of the core open protocols supported by their HMIs, allowing integration with a wide range of third-party controllers and devices over Ethernet. This makes it a common choice for connecting HMIs to PLCs when native drivers are not used or when working in mixed-vendor environments.
In practice, Modbus TCP is used to:
- Read process data from PLCs into the HMI
- Write control values from the HMI to the PLC
- Enable communication between devices from different manufacturers
Overall, Modbus TCP provides a standardized and widely supported method for Ethernet-based communication, making it a foundational protocol for integrating HMIs into industrial automation systems.
Implementation of MODBUS TCP
There is no single “MODBUS TCP PLC”. Instead, there are hundreds! MODBUS, being an industry-standard communication protocol, is prevalent in many PLCs and other industrial devices. The beauty of this is that the device doesn’t need to have a proprietary communication and control system; using MODBUS TCP allows for communication to an incredibly wide variety of devices