Test set up : The empty Ottawa Cell is loosely fixed onto the machine base. The plunger is attached to the load cell carrier and is lowered slowly into the Ottawa Cell The Ottawa Cell is then manoeuvred until clearance is visible between the plunger and the sides of the cell The Product Catchment Drawer is positioned under the Ottawa Cell, to catch the extruded sample. The plunger is then raised above the cell to allow for placement of the test sample. Before carrying out the test using a Button trigger one must calibrate the plunger to acknowledge the bottom of the cell as a zero position. To do this, lower the plunger, so that it is close to the bottom of the cell. Click on T.A. (in the menu bar) thenCALIBRATE PROBE. Specify the distance that you want the plunger to start from for each test-e.g. 70mm is suggested. The plunger will move down and touch the extrusion plate and then move up to the specified start distance. For the comparison of results it is crucial that the test always begins at the same distance from the bottom of the cell, this distance can be programmed into the CONTROL PROBE feature Prior to each test ensure that there is good clearance around the phunger to avoid frictional effects. This can be checked by running a blank' test i e, one without any sample in the cell, to ensure that the plunger is not touching the sides. The plunger is then raised above the cell to allow for placement of the test sample. Place the sample into the cell, distribute crisps evenly and run the test. In between tests clean the plunger, extrusion plate, and the inside of the cell to remove any remaining sample, as this will cause variable results.