GC Oven Temperature Ramps (7697A)
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GC Oven Temperature Ramps

    With GC-HS communications enabled and with Follow GC enabled, the GC oven ramps are already known and the software hides these settings.

Most GCs allow you to prepare a program of levels (or "ramps"), executed in consecutive order, to control oven temperature during a run. When using HS carrier gas control and a flow control mode, the HS needs to know how the column temperature will change during the run so that it can properly maintain the carrier gas flow. Use the GC Oven Ramp table to describe the GC oven ramp program. The HS can support up to 10 GC oven ramps.

A ramped oven temperature program includes:

  • An Initial oven temperature value
  • Multiple oven temperature Ramps

Specify the following parameters for the existing GC oven temperature program:

  • Initial Value (in °C/min) and Initial Hold Time (min): Enter the GC oven starting temperature, and the time the GC remains at this temperature. For an isothermal GC run, no other entries are needed.
  • Rate: Rate (in °C/min) at which the GC heats or cools the oven from Value on one program level to Value on the next program level. This constitutes a "temperature ramp." Enter a rate of zero at any level to disables the oven temperature program for that level and any which follow.
  • Value: The temperature (in °C) to which the GC heats or cools the oven for a given program level. For isothermal (constant temperature) runs, set the Value parameter in the top row of the table to the desired temperature, then set the first Rate to 0.0 to disable any ramps. The initial Value is the oven temperature at the start of a run.
  • Hold time: The number of minutes the GC is to maintain a temperature Value for each given program level. The initial Hold time begins when the HS starts the run.

The total Run Time (cumulative run time through each ramp level) displays for reference. The Run Time includes all entered ramp times and hold times.

    Always update the HS method oven temperature program so that it matches the current oven temperature program. Otherwise, the HS may not control carrier flows or pressures as accurately as expected.

See also:

To Program a Ramp