# Calibration Plate Measurements

## The BCAM Calibration Plate

Figure 1: The BCAM Calibration Plate. For a larger view click here.

Each section below gives the positions of the three quarter-inch steel balls on a plate like that shown above. Each section applies to a particular plate and a particular measuement of that plate. We present each measurement in our text-only database record format.

We number the spheres on each plate 1 through 3. Sphere 1 is the front sphere. Sphere 2 is the rear-right sphere, which lies under the slot of a black BCAM and the flat of a blue BCAM.

We give the coordinates of each ball in millimeters. The origin of the coordinate system in which we specify the ball positions is at the bottom front-left corner of the plate, as marked on the drawing. The x-coordinate is the first number we list for each ball, and lies along the front edge of the plate. The y-coordinate is straight up, and the z-coordinate is away from the plate so as to complete a right-angle coordinate system. We note that the coordinates in which we provide the ball measurements are not the same as those used by the CMM upon which we measured the ball positions. The CMM's coordinate system has z upwards instead of y.

We mark the name, or the number, of each pen upon each plate in paint or ink. In case the ink washes off, we also try to punch a letter or number identifying the plate into its top surface. This letter or number might be small, so look carefully for it before you decide it is not there.

## Plate 1

```apparatus_measurement:
calibration_type: single_calibration_plate
apparatus_version: OSI1
measurement_time: 20040908171200
operator_name: Jim
data:
50.784 14.508 -25.567 {sphere 1}
29.792 14.519 -98.558 {sphere 2}
71.749 14.548 -98.562 {sphere 3}
end.
```

## Plate 2

```apparatus_measurement:
calibration_type: single_calibration_plate
apparatus_version: OSI2
measurement_time: 20040908170601
operator_name: Jim
data:
50.785 14.572 -25.549 {sphere 1}
29.795 14.556 -98.542 {sphere 2}
71.753 14.568 -98.547 {sphere 3}
end.
```

## Plate 3

```apparatus_measurement:
calibration_type: single_calibration_plate
apparatus_version: OSI3
measurement_time: 200409081728221
operator_name: Jim
data:
50.781 14.544 -25.385 {sphere 1}
29.788 14.526 -98.418 {sphere 2}
71.749 14.554 -98.418 {sphere 3}
end.
```

## Plate 4

```apparatus_measurement:
calibration_type: single_calibration_plate
apparatus_version: OSI4
measurement_time: 20040908173717
operator_name: Jim
data:
50.796 14.547 -25.565 {sphere 1}
29.787 14.521 -98.557 {sphere 2}
71.745 14.544 -98.565 {sphere 3}
end.
```