Installation and commissioning progress of the 2PACL CO2 cooling control systems for Phase II upgrade of the ATLAS and CMS experiments

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.