RIEVTECH STUDIO SOFTWARE MANUAL You can realize theconnections by using the “ Ethernet PLC ” mode, such as multi HMIs, multi HMIs and one PLC,multi HMIs and multi PLCs, and other connections. 4.10.3.3 Service Servicerefers to that the HMI device providesthe data requested by other devices. The HMI is a slave device. The portis static. All communication operations should be initiated by other master devices. The type of Service includesSerial Port Service and Network Service. 4.10.3.3.1 Serial Port Service 465