Resistance Measurements - HP 3457A Service Manual

Operation
T o select the Integration Time
-
Press the NPLC
/
A configuration key, use the ?/AUTO o r &/HOLD
scroll key t o display the desired number and press thc ENT
/
LAST ENTRY hey.
The Integrcttion Time cct~r ctlso bc c-hartgetl by pves~irzg the NPLC/A k e y , ivttc.r.irtg tlte r l d v r r l rtnrrrbcr directly, artd pressirtg
tlre ENTILAST ENTRY k r y .
3-16. lnput Connections. For voltage
measurements,
the input voltage is connected t o the INPUT HI and L O
Terminals. This is true f o r both Front and Rear Terminal operation. When i~sing one of the optional
Plug-In asseniblies, the input is connectcd t o the HI and L O inputs of a particular cllannel.
3-17. Frontpear lnput Selection. The Input configurations are Front Tcrrninals, Rear Termiuals/Scanner
o r Open. Only one i n p ~ ~ t configuration (front, rear, scanner or open) can be selectctl a t a time.
T o select Input configuration
-
Press the TERM
/
M configurnlion key. Use the ?/AUTO o r &/HOLD
scroll key t o display the desired input and prcss the ENT
/
LAST ENTRY hey.
3-1 8. Resistance Measurements (Manual Operation)
3-19. Function Selection. The measurcnient function is selected by pressing thc appropriate function key.
T h e resistance measurement functions available are 2-Wire Ohms and 4-Wire Ohms.
T o select 2-Wire resistance measurements
-
Press the OHM
/
OHMF function key.
T o select 4-Wire resistance measurements
-
Press the Blue SHIFT key then the O H M
/
OHMF hey.
3-20. Range Selection. T h e Auto-Range feature automatically selects the appropriate range for the resis-
tance being measured. The Auto-Range feature is disabled by selecting Manual Ranging. There are
9
resis-
tance measurement ranges available;
30
Ohms,
300
Ohms,
3
UOhms,
30
KOhms,
300
KOhrns,
3
MOhms,
30
MOhnis,
300
MOhnis and
3
GOhnis. The extended ohnis ranges
(300
MOhms and
3
GOhms) are available
only f o r 2-Wire resistance measu1-ements. The default mnge is Auto-Range.
T o select Manual Ranging and maintain the present range
-
Press the Blue SHIFT key then the
FR HOLD
scroll key.
T o select Manual Ranging and the next higher range
-
Press the ?/AUTO scroll key.
T o select Manual Ranging and the next lowser range
-
Press the
HOLD
scroll key.
T o return t o Auto-Ranging
-
Press the Blue SHIFT hey then the ?/AUTO scroll hey.
3-21, Measurement Resolution. Measurement Resolution is changed by selecting the number of digits dis-
played. You can choose a display of 3 1/2, 4 1/2, 5 1/2 or 6 1/2 digits. The 1/2 digit refers t o the most sig-
nificant digit which is limited t o a value of
0, 1, 2,
or
3.
The default number of digits displayed is
5 1/2
(most significant digit plus
5
digits).
T o change the number of digits displayed
-
Press the DIGITS DISP
/
P configuration hey, enter the
number
3,
4,
5
or
6 and press the ENT
/
LAST ENTRY key.