> For the complete documentation index, see [llms.txt](https://docs.enlyze.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.enlyze.com/en/connect/ot-connectivity/supported-industrial-protocols/s7-classic/known-issues.md). # Tips & practical notes Tips and practical notes for operating the S7 Classic connector. This page collects tips and practical notes for operating the S7 Classic connector with Siemens S7-300 and S7-400 controllers via the [S7 Classic protocol](/en/connect/ot-connectivity/supported-industrial-protocols/s7-classic.md). ## Controller not found by Data Source Discovery **Data source discovery** in ENLYZE EDGE currently finds PROFINET devices only. Controllers connected through a PROFIBUS/MPI adapter, and CPUs without a PROFINET interface, do not show up there even though they are reachable via S7 Classic. If you know the IP address of the controller or adapter, check reachability with the [network tools](/en/connect/edge-device/enlyze-edge/network-tools.md) and the **PLC Info** under **Data source tools** > **S7 Tools** instead. ## PLC info shows some sections as unavailable PLC info queries several information sections of the CPU separately. Some PROFIBUS/MPI adapters and CPUs do not answer all of them, for example **Component identification**. That section is then shown as **Unavailable**. As long as the **Order number** or **Operating mode** can be read, the connection works with the rack and slot values you entered. Data recording is not affected. ## Variables are not registered during import When importing from the STEP 7 project, variables with unsupported data types (e.g. `TIME`, `DATE`, `S5TIME`, `LREAL`, or arrays) are skipped. The import shows up front how many variables of which type are affected. All other variables are imported as usual. If you need such values, check whether the PLC program also provides them in a supported data type (e.g. a duration as `DINT` in milliseconds). For an overview, see [Supported data types](/en/connect/ot-connectivity/supported-industrial-protocols/s7-classic.md#supported-data-types). ## Importing the project folder fails * **The folder contains no `.s7p` file, or several**: select the folder that contains exactly one `.s7p` file, i.e. the project folder itself, not its parent folder. * **You only have the `.s7p` file**: the variables are stored in the project's subfolders. Ask for the complete project folder. * **The project is an archive**: extract the archive (`.zip`) first. You can open archives from SIMATIC Manager via **File** > **Retrieve** or with any common unzip tool. ## Data source is online, but one variable delivers no values If the controller cannot deliver a single variable, the connector keeps recording all other variables and the data source stays online. Common causes: * The data block no longer exists on the controller, or it is shorter than the address, for example after a change to the PLC program. * The data type does not match the address. In that case, import the variables again from the current STEP 7 project. Existing variables are updated. If the problem persists, contact us at . ## Many variables on one data source S7 Classic reads variables in packets whose size the CPU defines. On an S7-300 these packets are comparatively small. This is why the number of variables that can be recorded per data source is limited. The connector automatically combines addresses that are close together. Select only the variables you need for your analyses. If the limit is not enough, contact us at . If you have any questions, feel free to contact us at .