Rainwater harvesting system

Description
This compact SCL function block, FB_RainwaterSwitching, controls a rainwater pump with automatic switching to drinking water in the event of a leak or low fill level. It supports manual and automatic operation and provides a clear HMI status. Seamlessly deployable in the Siemens TIA Portal.

Note: All modules are designed exclusively as a learning and optimization basis and are not approved for live operation. System modules, in particular, must be finally tested and commissioned by qualified personnel before productive use.

How it works

1. Leakage detected → Pump off, drinking water switchover, alarm on, HMI "LEAKAGE", RETURN
2. System OFF → Pump off, drinking water active, HMI “OFF”, RETURN
3. Manual operation → Pump ON (rainwater), HMI “MANUAL: Pump ON”
4. Automatic mode → Check fill level

• ≥ Minimum fill level → Pump ON (rainwater), HMI "OPERATION: Rainwater"
• < Minimum level → Switch drinking water, alarm on, HMI "SWITCHING: Drinking water"

Technical details
• Inputs: Leakage, On_Off, Manual Mode, Level, Minimum Level
• Outputs: Pump_ON, Switch_Drinking_Water, Alarm, StatusText_HMI
• RETURN in case of leakage or switched off system interrupts all subsequent actions
• IF/ELSIF logic clearly separates manual and automatic operation

Possible applications
• Rainwater harvesting systems in buildings and industry
• Garden irrigation systems
• Fire protection reserve pumps
• Retrofit of rainwater tanks to ensure supply

compatibility
• Siemens S7-1200 & S7-1500
• TIA Portal V13 or higher; recommended V16+ for PLCSIM & HMI

Scope of delivery
• .scl file with input/output declarations, state logic and comments
• Download link immediately after purchase

Support
Adaptation to other level sensors, additional pump stages, or HMI designs, as well as logging functions, are available upon request. Contact me via shop message or email.