Agilent Technologies G1323B User Manual page 67

Using the Pump 3
Adjusting Compressibility
When the compressibility setting is set to Off, the pump makes no
compensation for the compressibility of the mobile phase.
For each particular compressibility value, the piston stroke (distance piston
moves) and the speed at which the piston moves are adjusted accordingly,
compensating for the solvent compressibility. For a mixture of solvents we
recommend that you choose the compressibility value of the solvent that is
present in the highest amount.
1200 Series Handheld Control Module Users's Guide 67