A method of controlling assay timing in a clinical analyzer that uses discrete reaction cuvettes for each assay, said method comprising, (a) identifying the type of test to be made in the clinical analyzer for each desired assay, (b) determining the sequence of sample dispensation, reagent dispensation and read operation to be performed for each identified test and a predetermined time duration between each such activity for each identified test that will provide a set of predetermined incubation times for each assay, wherein the predetermined incubation times can be of any selected time duration, (c) providing a cuvette carrier that moves cuvettes along a closed geometrical path, (d) scheduling the sample dispensation, reagent dispensation, and read operation for each assay to allow for the predetermined incubation times for each assay and permit all activities for all assays to be carried out without the operation of one activity interfering with the operation of another activity, (e) determining a discrete cuvette position for each assay on the cuvette carrier based on the schedule of activities, characterized in that said method comprises (f) moving all of the cuvettes on said cuvette carrier in unison, in multiples of incremental steps, along the closed geometrical path, in sequential predetermined time cycles, with incremental movement being made during each time cycle, such that each cuvette progresses to a different incremental position on the closed geometrical path during each time cycle, and the predetermined incubation times of any time duration are a multiple of the time duration of the predetermined time cycle, and (g) when at least one cuvette is scheduled to receive sample or reagent in a particular time cycle, moving the one cuvette with the cuvette carrier from the position of the one cuvette in that particular time cycle, to a sample delivery location for sample dispensation, or to a reagent delivery location for reagent dispensation. (a) identifying the type of test to be made in the clinical analyzer for each desired assay, (b) determining the sequence of sample dispensation, reagent dispensation and read operation to be performed for each identified test and a predetermined time duration between each such activity for each identified test that will provide a set of predetermined incubation times for each assay, wherein the predetermined incubation times can be of any selected time duration, (c) providing a cuvette carrier that moves cuvettes along a closed geometrical path, (d) scheduling the sample dispensation, reagent dispensation, and read operation for each assay to allow for the predetermined incubation times for each assay and permit all activities for all assays to be carried out without the operation of one activity interfering with the operation of another activity, (e) determining a discrete cuvette position for each assay on the cuvette carrier based on the schedule of activities, characterized in that said method comprises (f) moving all of the cuvettes on said cuvette carrier in unison, in multiples of incremental steps, along the closed geometrical path, in sequential predetermined time cycles, with incremental movement being made during each time cycle, such that each cuvette progresses to a different incremental position on the closed geometrical path during each time cycle, and the predetermined incubation times of any time duration are a multiple of the time duration of the predetermined time cycle, and (g) when at least one cuvette is scheduled to receive sample or reagent in a particular time cycle, moving the one cuvette with the cuvette carrier from the position of the one cuvette in that particular time cycle, to a sample delivery location for sample dispensation, or to a reagent delivery location for reagent dispensation.