HP 53150A Series Programming Manual page 161

Chapter 4 Command Reference
Common Commands
*WAI
(Wait-to-Continue Command)
*WAI
COMMENTS
This command prevents the instrument from executing any further
commands or queries until all pending operations are complete. The only
way to cancel this "holdoff" is by device clear, power-on, *RST, or *CLS.
See the section titled "Using the *WAI Command" on page 3-49 for an
example that uses this command.
None
RELATED
FRONT-PANEL
KEYS
Programming Guide 4-61