# Sharing the Hardware

While a PLC program runs, the OpenPLC Runtime scans the backplane continuously and controls the T/F toggle switch and the RGB LED. The `synergy_logic` and `Synergy` libraries access the same hardware. Running both simultaneously produces bus faults on the runtime and invalid readings in the user application.

**Stop the PLC or stop the runtime before running any Python or C++ program that accesses the backplane, the toggle switch or the RGB LED.**

## Stop the PLC or stop the runtime

Both release the backplane, the toggle switch and the RGB LED. They differ in what remains running:

| | Stop the PLC | Stop the runtime |
|---|---|---|
| How | Press **Stop** in OpenPLC Editor | `sudo docker stop openplc-bootloader openplc-runtime` |
| PLC program | Stopped | Stopped |
| OpenPLC Runtime | Running | Not running |
| Editor connection | Available; **Run** resumes the program | Unavailable until the runtime is started again |

Both last until the next reboot.

The bootloader supervises the runtime, so stop it first. To start the runtime again without rebooting:

```bash
sudo docker start openplc-bootloader
```

## Permanent disable

To run a Python or C++ program on the backplane at boot, prevent the OpenPLC Runtime from starting automatically. The `openplc-bootloader` container starts and supervises `openplc-runtime`, so only the bootloader's restart policy changes:

```bash
sudo docker update --restart=no openplc-bootloader
sudo docker stop openplc-bootloader openplc-runtime
```

Restore the factory setting with:

```bash
sudo docker update --restart=unless-stopped openplc-bootloader
sudo docker start openplc-bootloader
```

See [Running on Boot](running-on-boot.md) for configuring the user program to start automatically.