Waters Autospec Premier Operator's Manual page 101

Example voltage SIR function editor for TCDD
13. Select the required Ionization Mode.
This mode must be the same as the ionization mode in the selected
Rule:
AutoSpec parameter file.
14. Set Primary Lock Span (pw) to 2.
Doing so allows the instrument to compensate for an
Rationale:
approximate 100 ppm mass drift between calibration and acquisition.
15. Set Secondary Lock Span (pw) to 1.
Example of VSIR experiment set up 3-37