Case Study: Remote Deployment Server for 485 Local Intranet Data Acquisition

In this case, the client required on-site deployment of smoke detectors, temperature and humidity sensors, and water leak sensors. Sensor data must be transmitted via an internal network and must not be connected to the external internet. Local services need to be deployed on a local server and must not upload data or connect to the external internet to prevent data leaks or cyber attacks. Due to the impact of the pandemic, software personnel were unable to travel to the site for local service deployment. It was necessary to commission a local construction team for remote deployment, which required the use of a remote VPN.

The VPN router supports VPN connections between multiple local area networks (LANs), enabling various LAN applications such as server deployment.

VPN operates at Layer 2 of the network. It transmits Layer 2 broadcast packets from one LAN to another via the VPN, making two geographically separate LANs function as if they were a single LAN. Using the same subnet for VPN connections results in faster data transmission speeds and makes it easier to identify the cause of network faults during troubleshooting.

The VPN router obtains internet access via a 4G router. When remote assistance is needed, simply insert a SIM card to connect to the external internet.

Locally, a daisy-chain wiring method using RS-485 is employed, with the bus drawing power from the 24V power supply at the gateway section. The RS-485 gateway locally collects data from water leak sensors, smoke detectors, and temperature/humidity sensors. It reports immediately upon detecting anomalies and periodically sends heartbeat packets over the internal network when no anomalies are present.