The TU5200 is not reading RFID tags for comparison to the TU5300. How is this resolved?
TU5200 TU5300 RFID Compare-Tag Recognition
Software update 1.02 of the TU5200 resolves issues with the Link2SC or Compare-Tag Recognition when using the RFID tag comparisons written by the TU5300 turbidimeter.
Information on verifying the software version and downloading the update are located in the article here.