Calibration

Calibration is how the cell learns exactly where a pallet station is. A cell whose stations have shifted will place boxes slightly off, and the error grows with every layer.

When to recalibrate

• After anything hits or moves a station.
• After the robot or its base has been moved.
• When the stack is visibly leaning, or boxes land a little further out on each layer.

If in doubt, calibrate. It costs a few minutes and it is not destructive.

Semi-automatic

You bring the robot to each measurement point yourself and confirm it. Slower, but it works when the station is far from where the cell expects it — which is exactly the case after something was knocked.

Automatic

The robot finds the points itself by touching the station. Faster, and the normal choice for a routine check. It needs the station to be roughly where it was, or the probe finds nothing.

Running a calibration program 1.2.1

Calibration programs are prepared by the integrator and exported to the robot with the project. On the live screen, an administrator finds them under Calibration programs and opens one.

The dialog shows the cell in 3D with the path the robot will follow drawn over it: each move, each probe with the surface it will touch, and the frame being measured. The list on the right names every step. Choose Semi-auto or Full-auto, then Start: the robot leaves HOME and the steps tick as it reports them.

In semi-auto, the robot stops before each probe and a translucent robot appears where the probe expects it to stand, with the arrow of the touch it is about to make. Use the jog to bring the real robot onto the ghost — the distance is shown — then press Probe now. In full-auto the robot chains every probe on its own.

Abort stops the robot at any time; the frame is never changed by an abort. Closing the dialog does not stop the run: it opens again on every screen while the run goes on.

Checking the result

The cell shows the correction it measured before applying it. A few millimetres is normal. A correction much larger than that means something really has moved — go and look before accepting it, because accepting a wrong measurement teaches the cell a wrong position.

If the probe finds nothing over its whole travel, or the correction is outside the accepted band, the cell refuses the result and says so. That is the system protecting you: fix the station, then calibrate again.