Control Concept

The chromatographic equipment in an analytical laboratory usually comprises instruments from different manufacturers and of various generations. Depending on whether individual devices can be controlled via a PC, they are referred to as either controlled or non-controlled devices.

Controlled Devices

Controlling devices makes high demands on the adaptability of a modern chromatography data system; for example, operation of individual components must be easy and thus device-independent. This means that input and representation of a specific control command (e.g., the pump flow) must always be performed in the same way, regardless of whether the instrument is by manufacturer X or Y.

Chromeleon provides the Chromatography BIOS and supports a huge number of device drivers. (For more information, refer to Device Communication  Communication between the PC and the Chromatography System (Chromatography BIOS) and  Device Drivers.) The advantages of a uniform user interface are as follows:

• Short training time for inexperienced users.

• Uniform, device-independent operation: The same commands are used for all systems.

• Transfer of methods: Chromatographic methods can usually be transferred from one system to another. This is why the corresponding device functions must be available on both systems.

• Clear and uniform documentation.

Non-controlled Devices

In rare cases, non-controlled systems are used, which means that the individual instruments are operated manually. Chromeleon only records the data. Two conditions must be fulfilled:

• The injection time is communicated to Chromeleon by connecting the Inject contact of the injection valve with a Remote Input of the system. This guarantees time synchronization between sample start and recording time.

• Detector data is transferred to Chromeleon as digital or analog data (via a serial interface or UCI Universal Chromatography Interface).

For more information, refer to  Device Communication.