Siemens 2130 alarm: Undervoltage in encoder supply

Sinumerik detects voltage drop in the 5V/24V supply of the encoder or ±15V of the D/A converter. It is an alarm from the Encoder / measurement area, and in the catalog it is listed as “Undervoltage in encoder supply”. On the machine you notice it like this: Eje pierde referencia, Alarm when energizing or after movements, May affect several axes.

On the shop floor it almost always comes from one of these causes: Cortocircuito en cable encoder, Internal power supply, Encoder defectuoso, Conector flojo. Rule out the most likely one on your machine first, before touching parameters or swapping anything.

Turn off/on NCK after repairing; rereference. Resetting without fixing the cause first only hides the problem: Siemens 2130 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: Note the affected axis, Disconnect the cable when diagnosing (with the drive powered off), Revisar conector encoder. That alone will tell you whether it is the program or whether you need to raise a maintenance job.

With Siemens 2130 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.

Always if it involves power or disappears when removing the cable. 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.