WebServer Setup

S7 PLC Buddy connects to your PLC using the S7 WebServer API — a built-in JSON-RPC interface available on S7-1200 and S7-1500 CPUs. You need to enable it and create a user account in TIA Portal before the app can connect.

Tip

If your plant disables the WebServer for security reasons, S7 PLC Buddy also supports connecting over OPC UA instead. See OPC UA Setup — note that OPC UA currently covers fewer features (no diagnostic buffer, alarms, or runtime info yet).

Supported CPUs

Family	Minimum firmware
S7-1500 (all variants)	V2.0
S7-1200	V4.1
ET 200SP CPU	V2.0
S7-1500 Software Controller	V21.0

Enabling the WebServer

1. Open your project in TIA Portal

   Double-click your CPU in the device tree to open its properties.

2. Enable WebServer

   Navigate to Properties → Web server and tick Activate web server on this module.

   Optional but recommended: enable Allow access via HTTPS only to encrypt all traffic.

3. Create a WebServer role

   Go to Security Settings → Users and roles → Roles (tab) and click Add new role.

   • Enter a role name (e.g. Webserver).

   Go to Runtime rights tab → Function Rights Categories → Runtime rights and select the respective PLC.

   • Assign the following rights:

     • Read process data of watch tables
     • Read process data
     • Read syslog buffer of the CPU
     • Read files
     • Read diagnostics
     • Acknowledge alarms

4. Create a WebServer user

   Go to Security Settings → Users and roles and click Add new user.

   • Enter a username (e.g. plcbuddy).
   • Set a strong password.
   • Assign the newly created role on previous step (e.g. Webserver).

5. Compile and download

   Compile the hardware configuration (Compile → Hardware) and download to the PLC.

6. Verify the WebServer is active

   Open a browser on the same network and navigate to https://<plc-ip>. You should see the Siemens PLC WebServer login page. Accept the self-signed certificate warning.

Network requirements

• Your PC must be able to reach the PLC on TCP port 443 (HTTPS). If your plant network uses a firewall, ask your network admin to open this port.
• S7 PLC Buddy does not use the classic S7 protocol (TCP 102) for this connection method. If you’d rather not use the WebServer API at all, see OPC UA Setup for an alternative.

Certificate warning

Siemens CPUs ship with a self-signed TLS certificate. S7 PLC Buddy accepts self-signed certificates by design — no additional configuration is needed. If your organisation has deployed a CA-signed certificate on the PLC, that is also accepted.

Troubleshooting connection failures

Symptom	Likely cause
“Connection refused”	WebServer not enabled, or port 443 blocked by firewall
“Invalid credentials”	Wrong username/password, or user not in WebServer user list
Timeout on connect	PLC IP wrong, or PLC not reachable from this network segment
Green status, then goes red	Session expired — the 60-second keep-alive will attempt silent re-login using the credentials you entered at connect time

See Troubleshooting for more details.