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TP7 fault finding
The probe fails to trigger when the stylus touches the workpiece, but the probe operates normally when the stylus is deflected by hand:
| PI 7-3 indicators | Possible causes | Remedy |
| ‘SEATED' LED ON | The trigger speed is too low. The stylus is too heavy. | Probe normally to the workpiece surface. Increase gauging speed. Refer to the section ‘Stylus selection' for recommendations. |
The probe will not arm or the probe does not stay armed after pressing the ‘RESET' button:
| PI 7-3 indicators | Possible causes | Remedy |
‘STD' LED ON ‘SEATED' LED OFF | Probe sensor faulty. Probe connections open circuit. | Remove probe and test by substitution. Check wiring from probe to PI 7-3 interface. |
The probe will not arm or the probe does not stay armed after pressing the reset button. The head LED is OFF:
| PI 7-3 indicators | Possible causes | Remedy |
‘TP7' LED ON ‘SEATED' LED OFF | Probe sensor faulty or damaged by collision. | Remove probe and test by substitution. |
False (‘air') triggers occur while the CMM is stationary:
| PI 7-3 indicators | Possible causes | Remedy |
‘TP7' LED ON ‘SEATED' LED operates normally | Probe sensor failure. Faulty connection in autojoint, probe head or wiring. Excessive vibration from external source. Excessive vibration from CMM. | Remove probe and test by substitution. Inspect autojoint pins, check continuity of wiring from probe to interface. Eliminate source or isolate CMM. Check air supply. Maintain CMM. |
False (‘air') triggers occur at gauging speed:
| PI 7-3 indicators | Possible causes | Remedy |
‘DAMPED' LED OFF ‘SEATED' LED operates normally | Stylus is too large or heavy. Excessive vibration from CMM. | Use stylus arrangements within recommendations. Check CMM air supply. Maintain CMM air bearing system. |
False (‘air') triggers occur at fast traverse speed:
| PI 7-3 indicators | Possible causes | Remedy |
‘DAMPED' LED OFF ‘SEATED' LED operates normally | Stylus is too large or heavy. Excessive vibration from CMM. Traverse speed is too fast. | Use stylus arrangements within recommendations. Check CMM air supply. Maintain CMM air bearing system. Reduce traverse speed. |
The probe does not rearm after taking a point:
| PI 7-3 indicators | Possible causes | Remedy |
‘TP7' LED ON ‘SEATED' LED OFF | The reset speed is to slow or the stylus has slowly deflected while moving off the work piece surface. | Ensure that the direction of gauging and back-off is normal to the workpiece surface. Refer to the section ‘Resetting the probe'. |
There is an unexpected loss of accuracy:
| PI 7-3 indicators | Possible causes | Remedy |
‘TP7' LED ON ‘SEATED' LED operates normally ‘DAMPED' LED is OFF at touch point | Stylus damaged or ball is dirty. Stylus is too large or heavy. The probe head is damaged or the mounting of the head to the CMM quill is faulty. The autojoint connector is damaged or dirty. The gauging speed has changed. The trigger level has changed. | Inspect and clean stylus ball or replace and requalify the stylus. Check that the stylus joints are tight. Use stylus arrangements within recommendations. Inspect and clean the autojoint connector. Refer to ‘Maintenance' section. Requalify stylus tips. |