Hplc is for analytical work where you are loading micrograms or sample onto the column at a time - the columns themselves are about 4.6 x 150 mm (they range but to give an idea of scale)
Preprative chdmostorgaphy is intended for dealing with grams of sample to be purified. Generally prep systems, such as dynamic axial compression chromatography or flash chromatography, lack the fine resolution for analytical chromatography but the trade off is increased sample loading. These prep systems, like the analytical systems, will have a detector and plot absorbable vs time like an hplc. But the two systems are not the same.
Now days UPLC is being more of the standard for analytical work.