Siemens 4000 alarm: Gap in axis assignment (machine data)

Sinumerik detects that the axis assignment to the channel is not contiguous in MD20070 AXCONF_MACHAX_USED. It is an alarm from the PLC/machine area, and in the catalog it is listed as “Gap in axis assignment (machine data)”. On the machine you notice it like this: NC not ready at start-up, The channel does not enable, Aparece tras modificar machine data.

On the shop floor it almost always comes from one of these causes: Incorrect edition of MD20070, Partial restoration, Configuration change without reviewing table, Axis removed without reordering. Rule out the most likely one on your machine first, before touching parameters or swapping anything.

Power the NCK off and on after fixing MD20070 and AXCONF_MACHAX_NAME_TAB. Resetting without fixing the cause first only hides the problem: Siemens 4000 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: Do not modify any more machine data, Anotar cambios recientes, Load OEM backup if available. That alone will tell you whether it is the program or whether you need to raise a maintenance job.

With Siemens 4000 active, avoid this: Do not edit machine data without backup, Do not restore partial parameters. Skipping any of these points is what turns a minor stop into an expensive breakdown.

Always: requires configuration adjustment with OEM backup. 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 critical: there is a real risk of damage to the machine, the tool or a person. Leave the machine stopped, do not keep resetting it to see if it goes away, and call maintenance before producing again. Guidance reference. Always confirm the full text in the exact machine/control manual.