Compact-cross direction C-frame scanner

A sensor apparatus comprising:

• a C-frame comprising a support with a first arm and a second arm that define a measurement gap that accommodates a sheet, wherein the first arm has a first proximal end and a first distal end and the second arm has a second proximal end and a second distal end;
• a first sensor that is mounted on a first position of the first arm and a second sensor that is mounted on a second position of the first arm, wherein the first and second sensors are spaced laterally apart along a length of the first arm;
• a first standardization tile;
• a second standardization tile which is spaced laterally apart from the first standardization tile;
• first means for maneuvering the C-frame laterally back and forth along a scanning path such that the first sensor measures a characteristic of the sheet from a first edge of the sheet to a mid-point of the sheet along a width of the sheet and the second sensor measures a characteristic of the sheet from the mid-point of the sheet to a second edge of the sheet;
• and
• second means for maneuvering the C-frame along the scanning path to a first calibration position where the first standardization tile calibrates the first sensor and to a second calibration position where the second standardization tile calibrates the second sensor.

A method of measuring process variables in a sheet process which has a machine direction and a cross direction, the method comprising:

• (i) providing a first elongated member that supports a first sensor and a second sensor, wherein the first and second sensors are separated laterally along the first elongated member;
• (ii) directing a sheet of material along the machine direction wherein the sheet has a first side and a second side and a first edge and a second edge and wherein the first elongated member is positioned along the cross direction adjacent to the sheet of material;
• (iii) maneuvering the first elongated member back and forth between a first scanning position and a second scanning position such that the first sensor measures a property of the sheet from the first edge to a mid-point of the sheet of material along a width of the sheet and the second sensor measures a property of the sheet from the mid-point to the second edge;
• (iv) positioning a first standardization tile adjacent to the first edge;
• (v) positioning a second standardization tile adjacent to the second edge;
• (vi) maneuvering the first elongated member to a first calibration position wherein the first sensor obtains reference measurements using the first standardization tile;
• and
• (vii) maneuvering the first elongated member to a second standardization position wherein the second sensor obtains the reference measurements using the second standardization tile.