Agilent Technologies E4406A, User Manual

Page: 180 / 230

180 Chapter 6
If You Have a Problem
Error Queues
Ext Ref
(external reference) - The green
Ext Ref
annunciator
indicates that the external reference has been selected and the
instrument is locked to it. The red
Ext Ref
annunciator indicates
that the external reference has been selected, but the instrument is
not locked to that reference. Note that the external reference on this
instrument can be set at any frequency between 1 and 30 MHz; if the
entered value does not correspond to the external reference that is in
use, a red
Ext Ref
annunciator will appear. Also, be aware that the
value entered for the external reference frequency will persist, even
after the instrument has been powered off. The user must manually
enter a new value for the external reference if a different value is
required, even if it corresponds with the default value. An
Ext Ref
annunciator will appear only if the external reference has been
activated by the user.
ESec
(even second clock) - The green
ESec
annunciator indicates that
the external even second clock has been selected as the sync type
and a sync signal is present at the even second input (rear panel
Trigger In), and the measurement is using it as the demodulation
sync type. The red
ESec
annunciator indicates that an external even
second clock has been selected as the sync type but a sync signal is
not present at the even second input (rear panel Trigger In). In this
case, the error message
Even Second Clock Missing
will appear in
the Status/Info bar at the bottom of the display. The even second
clock detection is updated every 2 seconds.
The History Error Queue
This queue is designed in a circular (rotating) fashion. It can hold up to
250 error messages. If the queue is full, and additional error messages
arrive, the oldest errors are lost. The previously read messages are not
cleared from the queue; they remain in the queue until they are
overwritten by a new error message.
The history error queue information can be accessed by pressing
System
,
Show Errors
. From this menu you can choose
Top Page
,
Last
Page
,
Next Page
, or
Prev Page
, to switch between pages (if there are more
than 17 error messages). To empty the queue, press
Clear Error Queue(s).
You can exit the error queue display by pressing either
ESC
or
Return
.
Selecting a measurement under the
Measure
key will also exit the error
queue display.