18SECTION 4 – INSTRUMENT SETUP4.1 INSTRUMENT NAVIGATIONTo navigate around the spectrophotometer screen press the arrow keys on the main keypad and usethe Enter key to select the highlighted option. Alternatively, some options and actions require the userto press the function and numeric keys on the instrument keypad. The Esc key can be used to returnto the previous menu without saving any changes.4.2 MAIN MENU SCREENMain Menu ScreenThe main menu screen provides access to allmeasurement modes, the system utility menuand the variable slit width setting. The availablemeasurement modes are photometrics,quantitation, spectrum scan, kinetics,DNA/Protein and multi-wavelength.The system utility menu option allows the user toperform a variety of setup and service functions.See section 4.3 for further details on theseoptions.4.2.1 Slit Width SettingThe slit width option allows the user to select the instrument’s bandwidth parameter from the availableoptions 0.5, 1.0, 2.0, 4.0 and 5.0 nm. Use the arrow keys to cycle through the options and press theEnter key to confirm. The instrument will perform a dark current calibration before returning to themain menu.