Commands and Tips for Third-Party Devices
Agilent 6890/6850 GCs: Application

Notes on the Device Driver:

General

Experienced 6890/6850 GC users should be able to control the instrument without any problems. In Chromeleon, short descriptions of the GC commands are available in the Command dialog box or the Properties/Link box.

In Chromeleon, pressure is always stated in bar and the pressure unit cannot be changed. For more information, please contact Dionex Service.

Inlet

The inlet is usually controlled by the use of Inlet.* commands. However, the inlet can be connected to the column via the PGM File or via a direct command, e.g., using

Column.Inlet = Front

The column commands also control the inlet. In this case, the last command overrides previous commands. For example, with the following command order

Inlet.Flow.Nominal = 20.0

Column.Pressure.Nominal = 5.00

the inlet flow is adjusted according to a column pressure of 5.00 bar, instead of being set to 20.0 ml per minute.

Also, refer to:

 Agilent 6890/6850 GCs: PGM File - Entering Pressure or Flow?

Cool On-Column Inlet

It is not possible to set both the temperature and Mode = TrackOven in the same program. If you attempt to do so, the following error message appears:

[Error] {FrontInlet} Can't set Temperature in TrackOven mode. Please set either a temperature or Mode = TrackOven, but not both.

Setting a temperature ramp automatically selects the RampedTemperature mode.

For a constant temperature, set Mode = RampedTemperature and enter a temperature value.

Column

It is possible to enter column dimensions and connections, but not the calibration. If column dimensions and connections are not defined, certain commands (Velocity, MakeupMode = Combined, etc.) cannot be executed

It is not advisable to enter the column dimensions and connections in a sample program. However, you should include them in the Audit Trail, using the Log command.

Valves

Chromeleon does not support certain valve types (Multiposition, Gas Sampling, etc.). For more information, please contact Dionex Service.

Aux

For the 6850 GC, one auxiliary device can be installed. For the 6890 GC, a maximum of two auxiliary devices for temperature control can be installed.

For both GC types, a maximum of three auxiliary devices for pressure control can be installed.

Sampler

For the 6890 GC, the extended capabilities of the 7683 autosampler, such as solvent prewashes, are supported. Note that these capabilities are not supported by the 7673 autosampler.

When Chromeleon connects to the 6890 GC or 6850 GC for the first time (see Connect), some (or many) error messages may appear, starting with Error log at. These are previous errors recorded by the autosampler and can be ignored.

Barcode Reader (only for the 6890 GC): If UseBCR = On, the barcode of the sample is read during the Inject command and is logged in the Audit Trail.

Parking the Sample Tray (7693 ALS Autosampler)

To move the sample tray to the park position, press the park button [P] on the front panel of the tray (for details, also refer to the operating manual of the sampler).

If you later want to perform injections, you must press the [P] button again to move the gripper from the park to the Home position.

Application

Entering a Temperature Gradient

You can enter a temperature gradient directly, either by selecting Flow on the Control menu (GC tab page) or by including a command in the PGM File.

For the 6890 GC, the temperature profile can include a maximum of six ascents or descents. (The 6890 GC cannot store more steps!) The maximum temperature change (ascent) is up to 120°C per minute, depending on the oven type.

Gradients are entered in the Program Wizard or online in the typical format for GC applications. (The starting and end temperatures are entered, as well as the modification rate.) In the program, however, the "base point philosophy" is used (similar to entering a flow or percent gradient in HPLC). Each temperature command is a base point of the gradient program. The wizard automatically converts the entered rates into the base point representation.

Temperature gradients can only begin after the Inject command. If a program does not contain an Inject command, this does not apply.

Temperature Setting Commands

Use the following commands to enable or disable temperature control of the oven, the inlet (two inlets for the 6890 GC), and the detector (two detectors for the 6890 GC):

Use the following commands to set the temperature of each module:

It may take some time for the instrument to reach the nominal temperature. Please note that the oven heats faster than the injector and the detector system. As soon as the nominal temperature is reached, the GC sends a Ready signal. An injection via the autosampler is possible only after this signal.

Example:

The following program waits until the nominal temperature of 150°C is reached before the Inject command is executed:

  0.000 GC.Temperature = 150

   Wait GC.Ready

   Inject

  ...... ..............

 Tip:

After the instrument has received the nominal temperature value from Chromeleon, it implements the desired value as quickly as possible. When the value is "almost" reached, the instrument waits until the user-defined Equilibration Time has elapsed before sending a confirmation message to Chromeleon.

Hardware Exchange

When you exchange the hardware, for example after hardware repairs, make sure to retrieve the configuration of the device afterwards to avoid system incompatibilities. Otherwise, the Audit Trail will report an error message.

To retrieve the configuration, do the following:

• Remove the driver from the timebase and then add it again.

• On the Select configuration mode page, click Get configuration from the instrument. The configuration will then be downloaded from the respective module to the Server Configuration program.

For troubleshooting information, refer to Agilent 6890 GC: Troubleshooting.

The Administrator Help section provides installation instructions for the 6890 and 6850 GCs; refer to Hardware Installation:

 Agilent 6890 GC: Installation

 Agilent 6850 GC: Installation