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.

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) or OPC UA — only the WebServer API.

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.