Data Acquisition

Even the best method of  Data Storage is only as good as the quality of the stored data. Therefore, data acquisition is a very important process, from the quality of the detector through all components participating in the data flow to data processing in Chromeleon.

A distinction is made between detectors supplying digital data and detectors supplying analog data. The best results are obtained with detectors that are capable of communicating digital signals directly to Chromeleon via a USB, serial, DX-LAN or other interface. (The Administrator Help section provides more information; refer to  Connecting Devices to the Chromeleon Server PC.) Detectors that supply analog signals must rely on precise conversion of the signals. The Dionex product line includes an extremely sensitive and low-noise UCI Universal Chromatography Interface for converting analog signals to digital signals. The UCI guarantees highest precision with minimum noise.

The following terms are important for data acquisition: Data Collection Rate, Sampling Rate, and Step. However, sometimes it may be difficult to understand the relationship between these terms.

The term Data Collection Rate is used if the detector directly supplies digital data to the PC. In contrast, the term Sampling Rate is used if an A/D converter, such as a UCI Universal Chromatography Interface, supplies the data. Both terms describe the number of data points recorded per second.

Step describes the time interval between two data points. By default, the step is the reciprocal value of the data collection rate or the sampling rate. Nevertheless, it is possible to select a different step. There is nothing particular you need to observe if an A/D converter supplies the data. However, for detectors supplying digital data make sure to define the Step command after the Data Collection Rate command.