Commands and Tips for Third-Party Devices
Agilent 6890/6850 GCs: PGM File - Entering Pressure or Flow?

Depending on the inlet (or auxiliary device), you have to define pressure or flow in the PGM file. In addition, this depends on the column dimensions. The GC can calculate the flow from the pressure (or vice versa) only if the column diameter, the column length, and the film thickness are known. In all other cases, you have to enter the values required by the inlet or auxiliary device.

Whether the pressure or the flow must be entered also depends on the control mode to be used by the GC for the separation. The following control modes are available:

• Constant flow

• Constant pressure

• Flow ramp

• Pressure ramp

Known column dimensions

Unknown column dimensions

 Tips:  

If you want to work with a constant flow but if you do not know the column dimensions, you have to enter pressure instead of the flow nevertheless, e.g., for Cool-On-Column-Inlet. In this case, you have to determine the pressure by trial and error to achieve the desired flow.

Agilent does not support the applications for which the fields in the above table are empty. Agilent does not support the Purge Packed, Cool on Column and Split/Splitless inlets without ECP when the column dimensions are not known.

You can only operate the PTV inlet in the constant pressure/flow and pressure ramp modes if no column dimensions are defined.

You can only operate the Gerstel PTV without control mode.

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