Position-measuring device and method for operating the same

A method for operating a position-measuring device including a graduation carrier having at least one measuring graduation, position measurement electronics, a data memory, and a power supply, wherein the position measurement electronics include at least one scanner for generating position signals by scanning the measuring graduation, a processor for processing the position signals into position values, and an interface, wherein the data memory includes a first memory which is a volatile memory in which additional data from an additional data source are stored, a second memory which is a writable non-volatile memory into which additional data from the first memory can be transferred and stored, and a memory controller which controls transfer and storage of the additional data from the first memory into the second memory, and wherein the power supply includes an input stage having at least one energy storage in which energy from a main supply voltage is stored, a first output stage which produces a first supply voltage for powering the position measurement electronics using the energy stored in the energy storage, a second output stage which produces a second supply voltage for powering the data memory using the energy stored in the energy storage, and a voltage monitor which monitors the main supply voltage for a drop below a minimum value, the method comprising:

• turning off, by the voltage monitor, the first output stage of the power supply in response to a drop below the minimum value, and signaling the drop below the minimum value to the memory controller by a backup signal;
• and
• transferring, by the memory controller, at least a part of the additional data from the first memory into the second memory and storing the additional data in the second memory in response to arrival of the backup signal, wherein the memory controller processes the additional data prior to the storage in the second memory.