Xenon 1900/1902HD resolution for Data Matrix barcode is 5 mil (0.127 mm). However, this is a 'passport data' for a general purpose scanner, measured when reading an almost ideal 'paper labels' – Data Matrix symbols printed onto a white paper.
For DPM samples the resolution might be not as high as for the 'ideal labels' – even if the print quality is very good, the surface/substrate, on which the symbol is planted, affect the image quality in most cases.