Math Feature; Number Of Power Line Cycles Integrated; Digits Displayed; Number Of Readings Per Trigger - HP 3456A Operating And Service Manual

Model 3456A
NOTE
Pressing the E X P k e y before entering a
number will display
c. Recall. Any of the Registers can be recalled at any
time. By pressing the RECALL bUllon and the key for
the Register to be displayed. (Remember, the registers
are in white.) The Register's value is then displayed on
the front panel.
d. Clear-Continue. The CLEAR-CONTINUE but­
ton, when pressed, clears the display and continues with
the previous operation. This can be useful when ac­
cidently entering an incorrect number from the
keyboard. The Clear-Continue feature clears the incor­
rect number and starts a new measurement cycle. This
feature can also be used when a register is recalled and
no changes in the register are desired.

Number of Power line Cycles Integrated.

3-61.
3-62. This feature of the ·hp- Model 3456A allows you
to select the integration time from .01 to 100 power line
cycles in multiples of 10. Since a power line cyc!e of " I"
has a time period of 1160 second, 1/50 for the 50 Hz op­
tion, the intergration time is 1/60 or 1/50 second. The
Number of Power Line Cycles Integrated determines
measurement time. The slowest integration time of the
3456A is 1 00 Power Line Cycles Integrated and the
fastest is .01 line cycles. For good power line frequency
noise rejection (Normal Mode Rejection), use integra­
tion times of either I , 10, or 100 power line cycles. Use
the Store method in Paragraph 3-60 to select the various
integration times (Number of Power Line Cycles). The
default value of the Number of Power Line Cycles In­
tegrated is 10 (at Turn-on and Reset).
3-63_

Digits Displayed.

3-64. The 3456A can display either a 3, 4, 5, or 6 digit
reading. Select any of these digits using the Store
method in Paragraph 3-60. The Number of Power Line
Cycles Integrated determines the maximum number of
digits the 3456A can display. If the
Cycles Integrated are used, the 3456A can display from
3 to 6 digits. With .01 Integration Time the maximum
number of digits then is 4 and with . 1 Line Cycles In­
tegrated the maximum is 5. Five is also the number of
digits displayed at Turn-On or when the RESET button
is pressed.
Number of Aeadings per Trigger.
3·65.
3-66. The Model 3456A is capable of taking from I to
9999 Readings per Trigger. Selection of the Number of
Readings per Trigger is accomplished by using the Store
method in Paragraph 3-60. The selected number of
readings are executed each time the instrument is trig­
gered. Although the Internal, External, and Single Trig­
ger modes will take the selected number of readings, it
J + O.
I to 100 Power Line
may be advantageous to use the External or Single Trig­
ger modes. Using these modes, if a Single Trigger is sent
the 3456A starts taking the readings and stops when all
the readings are taken. Another trigger repeats the same
operation. An Internal Trigger also does the same thing,
but automatically triggers again when all readings are
taken. The default value of the Number of Readings per
Trigger at Turn-On or at Reset is
Settling Delay.
]·67.
3-68. This feature of the -hp- Model 3456A can be used
to delay the 3456A's input measurement for a
preselected time. before a measurement cycle (AID
operation) is started. The amount of Settling Delay is
selected by using the Store method in Paragraph 3-60.
In some modes (ACV, OHMS, and Analog Filter), a
delay value is selected by the instrument. These selected
delays are defined in Table 3-3 and can be changed to
another value by using the Store method. Any number
value from .001 second to 999.999 seconds (including 0)
can be chosen for a delay in any mode. To return a
3456A selected delay to its default value store any
negative number into the DELAY register.
Teble Default Delays.
3·3.
Set·U p Condition
3456A
DCV.
Filter On
Of
ACV ACV DCV,
Filter Off
+
ACV or ACV + DCV,
Filter On
100 K Range
Ohms,
t M Range
Ohms,
1 0 M Range
Ohms,
lOO M Range
Ohms,
1 G Range
Ohms,
3·69. Dptimizing the Aeading Rate.
3·70. The previous paragraph stated that the Number
of Power Line Cycles Integrated has an effect on the
Number of Digits displayed. In addition to that, the
measurement accuracy and power line frequency noise
rejection (NMR) are also affected. You can select a
faster reading rate with a low Number of Power Line
Cycles Integrated. But keep in mind that the 3456A's
measurement error increases and that the ability to re­
ject power line frequency noise rejection is lessened.
Table 3-4 gives some ideas on how to optimize the
3456A's reading rate.
3-71.

MATH FEATURE.

3-72. A variety of math operations can be done by the
Model 3456A. Use the
Keyboard to select a math operation and to enter values
into registers used by the math operations. Refer to the
Numbered Keyboard for the folJowing discussion and
make sure you know how to store values into registers
Operation
" I " .
DII.y (in second)
.650
.060
.BOO
,001
,008
.080
.080
,080
instrument's Numbered
3-1 1