Presentation / operationPage 1-12 ABB Control - AC 311SBC 260400 R1001-b 06.993.6. Power cuts or dropsThe 50 series central unit disposes of a time delay in order to save the necessary informationfor the next startup should there be a power drop or cut.Saving program internal data is only possible on the 50 series central unit which possesses anbattery. Prior configuration of the central unit is required to save all or part of the data (seechapter 5). If the configuration is absent then all functions and internal data will be reset to 0.The intermediate calculations of the functions used in the user program, necessary for thefollowing cycles, are placed in variables called historic variables. It is also possible to savehistoric variables.A power cut or drop occurring on a 40 series central unit will result in all the functions andinternal data being reset to 0.
