Write data to Siemens PLCs using Lenze’s HTTP service

With Cloud Logging you can read data from your Siemens PLC. However, you can also remotely write data to your Siemens PLC by using the PLC’s HTTP server in combination with Lenze’s HTTP service.

This enables you to easilyquickly, and securely make the necessary changes to values inside the PLC without the need for a VPN connection or additional software.

Activate the HTTP server on your PLC

First you’ll need to activate the HTTP server on your PLC.

  • Open your project in TIA Portal and open the [Device configuration] in the project tree on the left.
  • Double click the controller or right-click and select [Properties].
  • Go to [Web server]check “Activate Web server on all modules of this device”, and un-check “Permit access only with HTTPS”.

Create a watch table

A watch table provides an overview of variables and their current values as well as the option to edit these values. We’ll be adding a watch table to the HTTP server, but we’ll first need a watch table to add.

  • Open [Watch and force tables], in the project tree on the left, and press [Add new watch table].
  • Add all variables that you’ll want to be able to edit remotely.

Add the watch table to the HTTP server

Now that you’ve created a watch table, you can add it to your HTTP server.

  • Open the [Device configuration] in the project tree on the left and double click the controller or right-click and select [Properties].
  • Go to [Web server] > [Watch tables]add your watch table, and set the access to “Read/Write.

Additional security

We recommend to add a user under [User management] and give the access to write tags only to that specific user (i.e. an admin).

Set up an HTTP service

You now have an HTTP server, including a watch table, running on the PLC. Using Lenze’s online HTTP service you can easilyquickly, and securely access the HTTP server.