Siemens 2100/2101 alarm: NCK battery warning/alarm

Sinumerik warns of low or critical battery in NCK/control. It is an alarm from the Power supply area, and in the catalog it is listed as “NCK battery warning/alarm”. On the machine you notice it like this: Battery message when turning on, Risk of data loss if ignored, May call for preventive maintenance.

On the shop floor it almost always comes from one of these causes: Dead battery, Long machine time without change, Faulty battery holder or connection. Rule out the most likely one on your machine first, before touching parameters or swapping anything.

Reset after correct change and data confirmation. Resetting without fixing the cause first only hides the problem: Siemens 2100/2101 trips again and, in the meantime, you keep working with the machine in bad shape.

With the machine stopped and in a safe state, start with these checks: Back up data/NC/PLC if applicable, Seguir procedimiento OEM de cambio, Do not power down if the manual specifies replacement with power on. That alone will tell you whether it is the program or whether you need to raise a maintenance job.

With Siemens 2100/2101 active, avoid this: Do not bypass safety devices, Do not manipulate energized electrical cabinet, Do not continue producing if the alarm reappears. Skipping any of these points is what turns a minor stop into an expensive breakdown.

If you do not have a procedure or there is already data loss. If you are not sure how far it goes, stop the machine and report it: a repeat alarm always works out cheaper than a crash.

It is a warning: the machine carries on, but it is flagging something that will get worse if you let it go. Deal with it between parts, not at the end of the shift. Guidance reference. Always confirm the full text in the exact machine/control manual.