ABB AC 31, Technical Manual

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Presentation / operation
Page 1-12
ABB Control - AC 31
1SBC 260400 R1001-b 06.99
3.6. Power cuts or drops
The 50 series central unit disposes of a time delay in order to save the necessary information
for 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 an
battery. Prior configuration of the central unit is required to save all or part of the data (see
chapter 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 the
following cycles, are placed in variables called historic variables. It is also possible to save
historic variables.
A power cut or drop occurring on a 40 series central unit will result in all the functions and
internal data being reset to 0.