Nexa Edge only reads. It subscribes to the tags you choose and never writes a value back to a machine. It talks to Nexa over ordinary HTTPS, so the plant network needs no inbound port and no VPN, and it keeps sending through network cuts by buffering on the PC.

The PLC talks to the OPC UA server in its own protocol (for a Siemens S7-1500, TOP Server reads it over S7). Nexa Edge connects to that OPC UA server, usually on the same PC, and sends what it reads to Nexa over HTTPS on port 443. Nexa decides which tag is which signal of which machine; the gateway decides what may leave the network.

• A Nexa plan with machine telemetry. The machine Live tab and gateways are part of it.
• A Windows 10 or 11 PC (64-bit) at the plant that stays on, with administrator rights to install, and internet access to nexa.com.tn on port 443.
• An OPC UA server that exposes your machines’ tags, such as TOP Server, with a user name and password for Nexa Edge.
• The machine in Nexa. Each machine you connect exists as an asset, so you can link its tags to it.

About half an hour for a first machine, most of it spent choosing tags.

1. Download and install Nexa Edge on the plant PC.
2. Create a gateway in Nexa from a machine’s Live tab, and paste its token in tab 1 of the app.
3. Connect the OPC UA server in tab 2, and have the server trust the app’s certificate.
4. Send the tag list from tab 3, then link the tags to the machine in Nexa.
5. Set the sending rules in tab 4, if the plant wants to limit what leaves its network.
6. Start the service in tab 5, and watch the machine come alive on its Live tab.