Commands and Tips for Third-Party Devices
Perkin Elmer Autosystem (XL) and Clarus GCs: Pressure and Flow Ramps

Programming pressure ramps is very similar to programming temperature ramps. Different modes are available for controlling the pressure of the carrier gas and the inlet, but not all possible combinations are allowed. Therefore, Dionex recommends specifying the various properties in each PGM file. Ready Check then verifies whether the various PGM settings represent a valid combination.

The examples below show common combinations for a PPC column and a capillary inlet with a pressure controlled split flow. For more information, refer to PPC Fundamentals in the Perkin Elmer operating manual for the instrument.

Constant Pressure/pressure ramps for PPC columns:

 GC_1.TempCtrl =  On

 GC_1.Temperature.Nominal =  100

 ; setting of the pressure modes

 Column_1.CapCtrlMode = On

 Column_1.FlowMode = Pressure

 Column_1.VacuumCorrection = Off

 . . .

0.000  Column_1.Pressure = 10.0

 Wait GC.Ready

 Inject

 GC_1.AcqOn

 Column_1.Pressure = 10.0

0.500  Column_1.Pressure = 10.0 ; pressure ramp

1.500  Column_1.Pressure = 15.0 ; pressure ramp

2.000  Column_1.Pressure = 15.0 ; pressure ramp

 GC_1.AcqOff

 End

In PressOvenTrack mode, you can define pressure modes that follow the oven temperature to hold the column flow constant. In this mode, you may enter only an initial pressure value:

 . . .

 ; setting of the pressure modes:

 Column_1.CapCtrlMode = On

 Column_1.FlowMode = PressOvenTrack

 Column_1.VacuumCorrection = Off

 . . .

0.000 Column_1.Pressure = 10.0 ; initial pressure value

 Wait GC.Ready

 Inject

 GC_1.AcqOn

 . . .

2.000 GC_1.AcqOff

 End

Use the following modes to realize flow and velocity ramps:

Column_1.FlowMode = Flow

and

Column_1.FlowMode = Velocity.

Split flow control allows you to run step gradients, to specify the absolute flow, or to define the split ratio. For a split injection in a flow-controlled program (flow mode), refer to the example below. In the example, the split flow is increased after 0.5 minutes. (For more information on split and splitless injection techniques, refer to the Perkin Elmer operating manual for the instrument.)

. . .

; setting of the pressure modes

 Column_1.CapCtrlMode = On

 Column_1.FlowMode = Pressure

 Column_1.VacuumCorrection = Off

 Injector_1.SplitCtrlMode = Flow

; uses absolute split flow

 Injector_1.PurgeMode = Fixed

; uses a fixed purge flow

 Injector_1.PurgeFlow = 6.0

; sets the purge flow to 6.0 ml/min

 . . .

; Program

0.000 Column_1.Pressure = 10.0

 Valve1.On 

; split valve is open

 Injector_1.SplitFlow =  50.0

; sets the initial split flow

 Wait GC.Ready

 Inject

 GC_1.AcqOn

 Column_1.Pressure = 10.0

0.500 Column_1.Pressure = 10.0; pressure ramp

Injector_1.SplitFlow = 200.0 ; increases the split flow

1.500 Column_1.Pressure = 15.0; pressure ramp

2.000 Column_1.Pressure = 15.0; pressure ramp

GC_1.AcqOff

End

For installation details, refer to:

 Perkin Elmer Autosystem (XL) and Clarus GCs: Installation