Configuring S7-1200 Web Server with STEP 7 Basic V11

Overview

The SIMATIC S7-1200 CPU family integrates a built-in Web server that exposes diagnostic buffers, tag values, and user-defined HTML pages over HTTP. The feature is configured entirely through the TIA Portal engineering framework; it does not require WinCC Professional, and it does not require STEP 7 Professional on the engineering station for S7-1200 targets. Engineers migrating from STEP 7 Basic V10.5 to V11 (the first TIA Portal release that introduced project-side Web page handling for S7-1200) commonly ask whether they must upgrade their tooling license to enable the S7-1200 Web server. The short answer is that STEP 7 Basic V11 is sufficient. The longer answer, which follows, covers the firmware, licensing, functional scope, AWP command set, and limits of the Web server that the V11 generation ships with.

The S7-1200 Web server is intended as a lightweight diagnostic and operator visualization surface, not as a replacement for a WinCC SCADA runtime. It is suited for remote tag inspection, password-protected maintenance access, and embedding process graphics into thin-client or mobile browsers where the full WinCC Basic HMI stack would be over-specified.

STEP 7 Basic vs STEP 7 Professional V11: What Changes for the Web Server

STEP 7 Basic V11 and STEP 7 Professional V11 differ primarily in the PLC families they can target and in the optional editors they expose, not in the Web server configuration tasks they can perform against an S7-1200. The Web server project node, the user-defined HTML fragment editor, and the Web server activation checkbox are present in both editions when an S7-1200 CPU is selected as the target.

The official distinction between the two V11 editions is summarized in the table below for S7-1200 Web server use cases:

If your project is exclusively S7-1200, the V11 license tier you choose has no functional impact on what the Web server can expose at runtime.

Prerequisites: CPU Firmware 2.0 Requirement

The S7-1200 Web server is not available on every firmware revision. It was introduced with CPU firmware version 2.0 and is present on all subsequent firmware releases. CPUs shipped from the factory with firmware 1.x cannot expose the Web server pages even if the engineering project has the feature enabled; the CPU silently rejects the configuration or downgrades the Web server to disabled.

The minimum firmware versions for common S7-1200 CPU models to support the Web server are:

Firmware images are catalog-number specific. The correct .upd file must match the exact MLFB of the CPU installed in the slot, or the CPU will reject the update with diagnostic buffer entry 0xE0F1 "Firmware update file invalid".

Web Server Licensing Model

The Web server feature on the S7-1200 is licensed on the engineering station, not on the CPU. The CPU firmware contains the Web server runtime unconditionally; no runtime license key is required on the PLC to activate it. The engineering station requires a valid TIA Portal license that permits targeting the S7-1200.

STEP 7 V11 is distributed as both Basic and Professional variants. Both ship with the S7-1200 Web server configuration GUI; the difference is the set of CPU families each license authorizes you to attach to a project. Refer to the official Siemens TIA Portal licensing documentation for the authoritative current licensing matrix:

• Licensing STEP 7 and WinCC (TIA Portal) - Siemens official TIA Portal V20 documentation describing the License Key model for STEP 7 Basic and STEP 7 Professional editions.

Practical implications:

1. Buying STEP 7 Basic V11 is enough for an S7-1200-only Web server project.
2. Buying SIMATIC WinCC Basic V11 (a separate license that also enables STEP 7 Basic programming for the S7-1200) is enough for the same scope and additionally allows building KTP Basic Panel images.
3. Buying STEP 7 Professional V11 is unnecessary unless the project also needs S7-300 / S7-400 / S7-1500 targets.

The license key is delivered on a USB dongle or as a software license download, depending on the order. The TIA Portal License Manager handles activation and transfer between stations.

Enabling the Web Server in STEP 7 Basic V11

Once the project is open in TIA Portal V11 with an S7-1200 device inserted, perform the following configuration sequence:

1. Select the S7-1200 CPU in the project tree.
2. Open Properties > Web server.
3. Check "Activate web server on this module".
4. (Optional) Configure a non-standard port if port 80 conflicts with another service.
5. (Optional) Enable HTTPS and select a CPU-generated self-signed certificate, or import a customer certificate.
6. (Optional) Configure the user list: at minimum one user with read access; add a second user with write access if remote setpoint changes are needed.
7. Under Web server > User-defined pages, add HTML files from your project's HTML source directory. V11 introduces a project-side HTML editor; files added here are downloaded to the CPU on every project download.
8. Compile the project (Compile > Software (rebuild all)) and download to the CPU.

Web Server Functions and Limitations

The S7-1200 Web server exposes two families of pages:

1. Standard pages - generated by the CPU firmware:
   • Intro (start page, links to other pages)
   • Module Information (order number, firmware, serial, slot configuration)
   • Diagnostic Buffer (chronological event log)
   • Communication (connection statistics)
   • Variable Status (read-only tag inspector with manual update)
   • Variable Tables (custom watch tables marked as "accessible from Web server")
   • User-defined pages
2. User-defined pages - HTML authored in TIA Portal and downloaded to the CPU. Pages can embed AWP commands to read and write tags.

The Web server has hard limits that must be respected when designing a visualization. From the original V11 functional spec:

The Web server is explicitly not a SCADA. It does not provide:

• Trend curves / historical archives
• Centralized user alarms with acknowledgement workflows
• Recipes
• Multi-user role-based access beyond read / write
• Redundancy
• Automatic failover of Web clients

For those features, a WinCC Basic / Comfort / Professional HMI panel or a WinCC Runtime Professional SCADA is required.

AWP Command Reference

AWP (Automation Web Programming) is the markup syntax embedded in user-defined HTML that the CPU rewrites on download to bind tag names to live values. The full set documented for S7-1200 in TIA Portal V11 includes:

A minimal user-defined page that exposes a tag for reading and writing would look like this:

<html>
  <head><title>Motor Status</title></head>
  <body>
    <h1>Motor 1</h1>
    <!-- AWP_In_Variable_Name ='"Motor1_Speed"' -->
    <p>Current speed: <!-- AWP_Out_Variable Name='"Motor1_Speed"' --></p>
    <form method="POST">
      Set speed (RPM): <input name='"Motor1_Speed"' size="5">
      <input type="submit" value="Apply">
      <input type="hidden" name='"Motor1_Speed"' :SET:>
    </form>
  </body>
</html>

After download, the CPU rewrites the file, replacing the AWP markers with the actual tag access code. Browsers see only standard HTML; they never see the AWP syntax.

Accessing the Web Server

From any client on the same subnet, browse to:

or, for a specific user-defined page:

If you enabled HTTPS, use https://<CPU-IP-Address>/ and accept the self-signed certificate warning on first access. Modern browsers will require explicit acknowledgement of the certificate risk.

Default port is 80 (HTTP) and 443 (HTTPS). If you configured alternate ports, append :<port>.

Security Configuration

The S7-1200 Web server is an operator surface and must be treated as one. Recommended baseline:

1. Always enable at least one user with a strong password. The default "No password" behavior must not be left enabled in production.
2. Enable HTTPS if the Web server is reachable from any network segment other than a locked-out engineering VLAN.
3. Place the S7-1200 behind a managed switch with port-based ACLs that restrict TCP 80/443 (or your custom port) to authorized clients.
4. If a write-capable user is enabled, ensure the application code validates any value submitted via the Web server. The CPU will write any value of the declared tag type (BOOL, INT, REAL, STRING, etc.); there is no field-level validation by the Web server runtime.
5. Use a separate CPU user account for the Web server versus for the TIA Portal engineering connection. Disabling the Web server user does not block the TIA Portal online connection.

Comparison: Web Server vs WinCC Runtime

For small machines where the operator needs to see a handful of values and acknowledge a few digital inputs from a phone or shop-floor tablet, the Web server is the lower-cost path. For anything that requires trend history or alarm workflows, plan for WinCC.

Verification and Commissioning Checklist

Before declaring the Web server project live, run through the following verification steps:

1. Firmware check: CPU reports firmware 2.0 or higher in TIA Portal "Online & Diagnostics > Module Information".
2. Configuration loaded: Project compiled without errors and downloaded to the CPU; the download log shows the user-defined HTML files being transferred.
3. Web server active: From a PC on the same subnet, browse to the CPU's IP. The intro page loads within 2 seconds.
4. User authentication: If a user is configured, the browser prompts for credentials and accepts the configured username/password.
5. Tag read: A user-defined page displays the live value of at least one tag and updates after a forced value change in the PLC.
6. Tag write: A write-enabled user submits a value via a form; the value changes in the PLC and is observable in a watch table.
7. Diagnostic buffer: The Web server diagnostic buffer page lists recent events; no Web-server errors are present.
8. Concurrent load: Three browsers connected simultaneously still load pages within 3 seconds.
9. Power-cycle retention: After CPU power off / power on, the user-defined pages still load without re-downloading the project.

Troubleshooting Matrix

FAQ