Abstract: A solid element for use as a control or calibration element which can be used in a diagnostic analyzer. The element includes a translucent or transparent solid material which when illuminated by a light source emits light corresponding to a specified concentration of a specific analyte as an analyte being measured.

Abstract: A raster input scanner particularly adapted for asynchronous operation for scanning a document original one line at a time in response to an external command. A document feed roll with step motor driver is provided to step the document across a scan slit one line at a time. To avoid the delay imposed while waiting for the document to come to a stop after each step, a control actuates the array to scan the document line at the same instant that the step motor is actuated whereby scanning occurs during the interval while the document is being accelerated by the feed roll.