When CAN-204 module reads data via Modbus, it will load the data received on the CAN bus into the cache in real time and wait for the Modbus command to read. After receiving the Modbus read command, the module will convert the specified CAN data and send it to the Modbus bus; when the module receives the Modbus send data command, it will directly process the Modbus data and send it to the CAN bus.