"Stop flow input activated" error for ACQUITY UPLC H-Class QSM when Startup runs in MassLynx - WKB98722

SYMPTOMS

• "Stop flow input activated" error for QSM when Startup runs in MassLynx
• ACQUITY QDa Mass Detector was in Standby when Startup initiated

ENVIRONMENT

• ACQUITY QDa Mass Detector
• ACQUITY UPLC H-Class Quaternary Solvent Manager (QSM)
• ACQUITY UPLC Binary Solvent Manager (BSM)
• ACQUITY UPLC I-Class Binary Solvent Manager (BSM)
• ACQUITY Arc
• 2525/2545 Binary Gradient Module
• 2535/2545/2555 Quaternary Gradient Module
• MassLynx 4.2
• MassLynx 4.1

CAUSE

ACQUITY QDa Mass Detector is in Standby, so the API gas is off.

FIX or WORKAROUND

1. Open Edit Shutdown or Startup from the Instrument shortcut in MassLynx.
2. Go to File > Open and select the Startup method (StartupMSandLC_ACE.acl is the most commonly used file).
3. Go to the Auto Control Tasks tab.
4. Highlight the Operate task in the Control Task list and hit the Delete Task button (second button from the right with the small red X above the Task list).
5. Highlight the first line in the Control Task list.
6. In the Task section on the left, select Operate from the pull-down menu.
7. Enter a Post Delay (s) time of 10.
8. Hit the Insert Task button (first button from the left with the single-headed arrow above the Task list).
9. Save the Startup method.

ADDITIONAL INFORMATION

Stop flow input activated is a feature designed to protect the instrument from a source flooding in the event that the API gas is lost. (shuts off or supply of N2 runs out). The default Startup method was designed for the free standing mass specs where the source gas is turned on separately from putting the system into operate. Thus the Operate task is after the Source Gas On task.

For the QDa, the source gas or API gas is tied directly to the Operate command. When the QDa is in standby the gas is off. For a system with a QDa, regardless of the pump or solvent manager, if the flow is started while the QDa is in standby, the system will trigger the Stop Flow because the API gas is off. For the QDa only, the Operate task must be in the Control Task list before the LC Pump On task.