Unintended system movement of the ysio max unit was reported.During preparation for an exam, the operator touched the 3d ceiling stand, and it moved without unexpectedly.The 3d collided with the bucky wall stand.No patient was present in the exam room.There are no injuries attributed to this event.The reported incident occurred in (b)(6).
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The issue was investigated in detail.During an investigation at the customer site, it was identified that prior to the reported event it was determined that the force sensor was defective and needed to be replaced.The reported event occurred following the discovery of the defect prior to part replacement.In general, it is recommended to take the system out of use as a precaution until the problem is solved.The investigation of the provided log files confirmed that the described issue was caused by a force-controlled movement.The sensor was defective in the z-direction.It was found that during the rotation horizontal axis was rotated from 0 ° to approx.57 °, the defective force sensor received incorrect z values.The user communicated that, as the tube stand was driving the wrong way, the operator wanted to hold it back.The machine detected a manual movement, the automatic stop is in general deactivated for manual movement.This resulted in a collision between tube stand and wall stand.The system provides multiple risk mitigating features, which are still within specs: force limitation of 200n (motor current measurement).Dead man switch - the movement continue only when a button is pressed.Emergency stop - the motor power supply will be interrupted as soon as the button is activated.According to the information received, the force sensor was replaced following the incident.Since the part replacement no further issues are have been reported.The spare part consumption of the concerned force sensor (material number 07042315) shows values that are below the defined threshold.No general problem is known.
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