In the scope of the High Luminosity Program of the Large Hadron Collider at CERN, the ATLAS and CMS experiments are progressing in the installation and commissioning of their environmentally friendly low temperature detector cooling systems for their new trackers, calorimeters and timing detectors. The selected “on-detector” cooling solution is the CO2 pumped loop concept which is the evolution of the successful 2PACL technique allowing for oil-free, stable, low-temperature control. These systems are of unprecedented scale and largely more complex for both mechanics and controls than installations of today. This paper will present a control system overview, applied PLC architecture and the installation and commissioning progress achieved by the EP-DT group at CERN over the last years. We will describe in detail homogenised solutions which spreads between surface and underground and have been applied for future CO2 cooling systems for silicon detectors at ATLAS and CMS. We will describe in detail applied multi-level redundancy for electricity distribution, mechanics and controls. We will discuss numerous controls-related solutions deployed for electrical design organization, instrumentation selection and PLC programming. We will finally present how we organised early control system commissioning as initial step for LHC Long Shut down 3.

By the end of 2024, to cope with needs of future ATLAS tracking detector (ITk), surface integration and testing facility at CERN was fully equipped with a new large power and low temperature cooling system nick-named “DEMO Inheritance” based on the 2PACL technique. This paper will discuss implemented control system solutions for both the cooling plant and the distribution system installed in the detector proximity at the assembly clean room. The PLC and SCADA software has been fully deployed, following CERN UNICOS framework and allowed for successful and rapid initial performance test with 50kW dummy load. In this paper we will describe in details SCADA and PLC based procedures used for automatic system performance tests with no operator attendance as the first step in future commissioning of the final detector cooling systems of ATLAS and CMS detectors at the High Luminosity era of the Large Hadron Collider at CERN. These procedures running unattended allow for significant commissioning time reduction which is a key requirement for very challenging schedule.