A cMT-series HMI connects to a Maple Systems Micro or Modular PLC using Modbus (typically Modbus TCP or Modbus RTU), allowing the HMI to read and write PLC data for monitoring and control.
The communication follows a standard Modbus architecture where the cMT HMI acts as the client (master) and the Maple PLC acts as the server (slave). The HMI sends requests to read or write data, and the PLC responds with the requested values or accepts written data. This is configured in EasyBuilder Pro using the appropriate Modbus driver.
There are two primary connection types:
- Modbus TCP (Ethernet)
The HMI connects to the PLC using an IP address over a standard network. This is the most common setup for cMT and Maple PLC systems. - Modbus RTU (Serial)
The HMI connects using RS-232 or RS-485 with defined communication settings such as baud rate and parity. This is typically used in smaller or legacy systems.
Data exchange is based on Modbus register mapping. The PLC stores data in registers (such as coils or holding registers), and the HMI is configured to reference those addresses. HMI objects then use those addresses to display values or send control commands.
A typical setup involves configuring the PLC with Modbus addressing, adding a Modbus device in EasyBuilder Pro, entering the connection parameters (IP address or serial settings), mapping HMI objects to the correct register addresses, and downloading the project to the HMI.
In operation, this connection allows the HMI to display real-time PLC data, send commands, and serve as the main operator interface for the system. Overall, the cMT HMI acts as a client that reads and writes PLC registers, forming the core communication link between the interface and the control system.