Tektronix MSO54, Programmer'S Manual

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Status and Events
Event Queue The Event Queue stores detailed information on up to 33 events. If than 32
events stack up in the Event Queue, the 32nd event is replaced by event code
350, "Queue Over
fl ow."
Read the Event Queue with the EVENT? query (which returns only the event
number), with the EVMSG? query (which returns the event number and a text
description of the event), or with the ALLEV? query (which returns all the event
numbers along with a description of the event). Reading an event removes it
from the queue.
Before reading an event from the Event Queue, you must use the *ESR? query to
read the summary of the event from the SESR. This makes the events summarized
by the *ESR? read available to the EVENT? and EVMSG? queries, and empties
the SESR.
Reading the SESR erases any events that were summarized by previous *ESR?
reads but not read from the Event Queue. Events that follow an *ESR? read are
put in the Event Queue but are not available until *ESR? is used again.
Event Handling Sequence
The following fi gure shows how to use the status and event handling system. In
the explanation that follows, numbers in parentheses refer to numbers in the fi gure.
MSO54, MSO56, MSO58, MSO58LP Programmer 3-5