What the Error Indicates
The Biesse Rover machining center reports a "Present sensor lacking" error when the control loses the presence signal from one of the three sensors mounted in the main head. These sensors are hidden behind a metal sheet cover, which is why the fault is often mistaken for an electronic failure when the actual cause is contamination. Metal debris and dirt accumulating on the sensor face can block detection, and the sensor most commonly affected is the second (middle) one of the three.
Cleaning the Middle Head Sensor
Remove the metal sheet covering the three head sensors to expose them, then clean the second (middle) sensor. The critical constraint is mechanical: the sensor is positioned with micrometers, so its exact mounting position must be preserved. Before disturbing anything, mark or record the sensor's position so it can be returned exactly as it was. A sensor reinstalled even slightly off its original setting can reproduce the fault or introduce positioning errors.
- Remove the metal sheet that covers the three sensors in the main head.
- Identify the second (middle) sensor and clean accumulated metal dirt from it, handling it carefully.
- Note the sensor's micrometer-set position before any adjustment, and reinstall it exactly as it was.
- Restart and verify the "Present sensor lacking" error has cleared.
When Cleaning Does Not Clear the Fault
If cleaning the middle sensor and restoring its position does not clear the error, the worst-case cause is a damaged sensor that requires replacement with a new unit. Because the source does not specify a part number, wiring diagram, or test procedure for confirming sensor failure, verify the replacement part against the machine's documentation or Biesse support before ordering, and transfer the micrometer-set position from the old sensor to the new one during installation.
FAQ
What causes the 'Present sensor lacking' error on a Biesse Rover?
The main head contains three sensors behind a metal sheet cover, and the error typically occurs when metal dirt accumulates on the second (middle) sensor and blocks its detection signal.
Where are the sensors on a Biesse Rover main head?
There are three sensors in the main head, concealed behind a metal sheet cover that must be removed to access them. The middle sensor is the one most commonly contaminated.
What should I watch for when removing a Biesse Rover head sensor?
The sensor is positioned with micrometers, so record its exact position before removal and reinstall it exactly as it was. If cleaning does not clear the error, the sensor is likely damaged and must be replaced.
