User manual

Front Panel Operation
2001-900-01 Rev. K/ August 2010 3-53
and rel is not enabled. If the value is within the limits shown
in Table 3-27, you are returned to the normal reading display
with that value of rel already enabled.
Previously stored rel values are converted if temperature or
AC voltage units are changed. For example, a rel value of
100 that was stored with units of DEG-C is converted to 212
if temperature units are changed to DEG-F.
Note that a bench or GPIB reset clears any stored rel values
and disables rel for all functions.
3.6.2 Enabling rel
From the normal reading display, the REL key toggles the rel
operation on and off. The present state is indicated by the
REL annunciator. Each time rel is enabled by the REL key,
the present reading becomes the new rel value for that
function. You cannot rel an overflow reading.
To make a new reading the rel value, rel must first be
disabled and then enabled again. Disabling rel does not clear
any stored rel value.
The present rel value for each measurement function can be
viewed from the CONFIG-REL display, as described in
paragraph 3.6.1.
When rel is enabled, the resulting reading is the algebraic
difference between the actual input value and the rel value:
With percent or mX+b math enabled, the rel’d reading is
acted on by the math operation:
A rel value expressed in dB or dBm is applied after the read-
ing is referenced to the selected level.
3.6.3 Multiple display of rel
One of the “multiple displays” allows you to view the
reading without rel applied on the bottom line of the display
and the rel’d reading on the top line. The display is available
by repeatedly pressing either the NEXT or PREVious
DISPLAY key to scroll through the multiple displays of the
particular function. The following is a typical message for a
rel multiple display:
+000.012 mVAC RMS
Actual=+001.012 (without REL)
3.7 Triggers
The following paragraphs discuss front panel triggering,
trigger configuration, and external triggering, including
example setups.
Model 2001 triggers are set up in the CONFIGURE
TRIGGER menu. The menu structure is shown and
summarized in Table 3-28. Some general rules to navigate
menus are given in paragraph 3.3.
3.7.1 Trigger model
The following information describes triggering of the Model
2001 from the front panel. The flowchart of Figure 3-22
summarizes front panel triggering. It is called the Trigger
Model because it is patterned after the SCPI commands sent
over the IEEE-488 bus to control triggering.
rel'd reading = actual value - relative value
displayed reading = math operation (rel'd reading)