The Tile Calorimeter (TileCal) is the hadronic calorimeter found in the central region of the ATLAS detector. It is a sampling calorimeter made of steel plates as absorber material and scintillating tiles as the active medium. The light produced as the particle crosses the scintillator tiles is transmitted by the wavelength-shifting fibres. PhotoMultiplier Tubes (PMTs) convert light into analog signals and transfer them to the next stage of the signal chain. The TileCal Detector Control System (DCS) main responsibility is to ensure the safe operation of the detector. This project aims to develop a plugin that will extract and analyse offline data for continuous analyses of the behaviour of the PMT High Voltage (HV) supply in order to detect unstable channels during the data taking periods. The data is provided by the dedicated DCS Data Visualization tool (DDV) through convenient API and then visualized using an interactive JavaScript plotting library. The plugin will be integrated into the Tile-in-One (TiO) platform that combines all TileCal offline data quality tools.