Heidenhain Stylus already in contact alarm: Stylus already in contact when starting scanning

The TNC detects stylus deflection before starting the probing cycle. It is an alarm from the Encoder / measurement area, and in the catalog it is listed as “Stylus already in contact when starting scanning”. On the machine you notice it like this: Fails when starting the probing cycle, Stylus touching part/tool, Incorrect approach position.

On the shop floor it almost always comes from one of these causes: Pre-position too close to the piece, Zero misplaced piece, Stylus doblado, Incorrect cycle geometry. Rule out the most likely one on your machine first, before touching parameters or swapping anything.

Reset after separating stylus and correcting geometry. Resetting without fixing the cause first only hides the problem: Heidenhain Stylus already in contact 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: Retract probe and check pre-position, Comprobar stylus visualmente, Check zero part/datum. That alone will tell you whether it is the program or whether you need to raise a maintenance job.

With Heidenhain Stylus already in contact active, avoid this: Do not force the probing, Do not move a deflected probe against the fixture. Skipping any of these points is what turns a minor stop into an expensive breakdown.

If the stylus is damaged or the probe does not calibrate. 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.