Cistern control / level monitoring

Description
This compact function block controls a pump with clear prioritization of manual operation and a reliable automatic mode based on level signals. The code, written in Structured Control Language (SCL), is ready for immediate use in the Siemens TIA Portal and is ideal for water or liquid supply applications.

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
The focus is on the manual mode: Using two buttons, the pump can be switched on and off using set/reset logic – with priority over all other functions. The automatic mode operates in parallel: As soon as the fill level exceeds a defined threshold, the pump is automatically activated. If the fill level falls below a minimum level, the automatic mode is immediately reset to prevent dry running.

The pump runs when either the manual or automatic latch is active - the logic ensures that the last command counts as long as there are no safety concerns.

Technical details

• Manual control via edge trigger ( rtr_ManOn , rtr_ManOff )
• Automatic mode via analog level values with triggers rtr_AutoOn and rtr_AutoOff
• Safety shutdown when the minimum fill level is reached
• Unique pump output ( Pumpe: BOOL ) for direct control of relays, contactors or HMI components
• Latch logic prevents flickering or unwanted state changes

Possible applications
Ideal for:

• Cistern and well pumps in building services engineering
• Water distribution in heating or cooling circuits
• Rainwater harvesting and process water systems
• Smaller industrial controls
• Training and demo environments with a focus on simple pump automation

compatibility
Runs on Siemens S7-1200 and S7-1500 controllers
Compatible with TIA Portal from version V13
Recommended: Version V16 or higher for PLCSIM, HMI connection and advanced simulations

Scope of delivery
You'll receive the complete .scl file with all inputs and outputs, trigger instances, and comments in the header. There you'll also find instructions for adjusting fill level thresholds, trigger logic, and parameters. The download is available immediately after purchase.

Support
I am happy to support you with:

• fine-tuning of limit values and switching thresholds
• integration into existing automation environments
• visualization on HMI or SCADA interfaces
  Just send me a message via the shop or email!