Failures in capacitive energy storages result in destruction of faulty elements and other expensive components. Recovery of such failures requires long-term and expensive works to replace and to restore elements of the capacitive energy storage. Diagnostic hardware of the capacitive energy storages makes it possible to limit the consequences of such failures, to reduce the frequency of their occurrence, as well as to monitor the equipment and transmit information on functioning of the pulse current sources to the facility. The operation of data acquisition system in high voltage facilities is accompanied by the electromagnetic interference, and it is therefore necessary to provide the optical fiber transmission lines, the isolation of the diagnostics hardware components and galvanic isolation of their power supply.