Okuma B2901/B2909 alarm: Address or sequence number failure

Okuma OSP detects programmed address or sequence number error in program logic. It is an alarm from the Program area, and in the catalog it is listed as “Address or sequence number failure”. On the machine you notice it like this: Falla en bloque concreto, Direction check or sequence number message, It happens after editing G-code.

On the shop floor it almost always comes from one of these causes: Incorrect NC address, Expected N number absent, Format not compatible with OSP, Postprocesador mal configurado. Rule out the most likely one on your machine first, before touching parameters or swapping anything.

Reset after correcting program. Resetting without fixing the cause first only hides the problem: Okuma B2901/B2909 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: Anotar bloque, Compare against the OSP manual, Validar postprocesador. That alone will tell you whether it is the program or whether you need to raise a maintenance job.

With Okuma B2901/B2909 active, avoid this: Do not delete the line without understanding it, Do not resume from mid-program without checking the modal states. Skipping any of these points is what turns a minor stop into an expensive breakdown.

Normally requires no maintenance. 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 stop alarm: the cycle will not continue until you fix the cause. It does not always mean serious damage, but it leaves the machine where it is and you have to check it before running again. Guidance reference. Always confirm the full text in the exact machine/control manual.