SFP2 calibration

Calibration of the SFP2 system is done for several reasons:

  • To map the rotation of the probe's C-axis.
  • To calibrate the SFH holder and SFM module geometry (including the knuckle angle)
  • To set the gain of each SFM module

There can be many different holder / module configurations attached to an SFP2.  Each arrangement must have its SFM module geometry calibrated and sensor gain found.  However, the probe's C-axis only needs calibrating once, and is good for all the SFH holders and SFM modules.  This mapping of the C-axis is applied together with the head and probe corrections.

SFAH-1 with SFA1

Mapping of the C-axis and calibration of the holder / module configuration geometry requires use of the TFP tip find probe with a TP20 LF low force module, which is mounted to an MRS or MRS2 system.

The probe's C-axis, and one holder / module configuration can be calibrated in the same operation.  Points will be taken on the SFH holder at three different C angles and then points will be taken on the SFM module.

NOTE:  If the probe's C-axis is remapped, all the module calibrations will be considered out of date and will require recalibration.

Any additional holder / module configurations require a module calibration routine which is a shortened calibration that takes one set of points on the SFH holder at a specific C angle and points on the SFM module.

Setting the sensor gain requires the SFA1-3.0 SIN calibration plate.  The calibration plate can be attached to an MRS / MRS2 rail or an MRS2 leg.  The gain calibration routine is run from UCCserver.  The part of the plate scanned during calibration is randomly set to minimise wear of the plate.

In addition to the SFA1-3.0 SIN calibration plate, there is an SFA2-0.5 SIN artefact to verify the linearity of the module if required.  There is also an SFA3-0.4 ST plate which is used to identify damage to the 2 µm radius diamond tip of the stylus.

These last two items are for use by the client software as required.

Calibration summary

Calibration of probe and first holder / module configuration

Function

Artefact

Pre-requisites

Status

Probe's C-axis mapping

Holder / module geometry calibration

TFP

None

Configuration not yet available for use.

Sensor gain calibration

Calibration plate artefact
(SFA1 - 3.0 SIN)

Probe's C-axis mapping and holder / module geometry calibration

Configuration can now be used.

Calibration of additional holder / module configurations

Function

Artefact

Pre-requisites

Status

Holder / module geometry calibration

TFP

Probe's C-axis mapping

Configuration not yet available for use.

Sensor gain calibration

Calibration plate artefact
(SFA1 - 3.0 SIN)

Probe's C-axis mapping and holder / module geometry calibration

Configuration can now be used.