Front Panel Operation
2-9
ing. The concepts of guarding and floating circuits are
introduced here.
NOTE
Detailed connection schemes are included
with the measurement procedures (see
paragraphs 2.5.1, 2.6.1, 2.7.1 and 2.8.1).
2.4.1 Electrometer input connector
The rear panel triax INPUT connector is a 3-lug female triax
connector that will mate to a cable terminated with a 3-slot
male triax connector.
Input configurations —
As shown in Figure 2-5, the input
connector can be configured in two ways. With GUARD off
(Figure 2-5A), input low is connected to the inner shell of the
connector. This configuration is used for current, resistance,
coulombs and unguarded voltage measurements.
NOTE
Where possible, make input low connec-
tions directly to the INPUT connector low
terminal instead of using COMMON to
avoid internal voltage drops that may af-
fect measurement accuracy.
With GUARD on (Figure 2-5B), guard is connected to the in-
ner shell of the triax connector. Input low is accessed via the
COMMON binding post through an internal 1
Ω
resistor.
This configuration is used for guarded voltage measurements
only. Note that guard can only be enabled (on) for the volts
function. For ohms, amps and coulombs, guard is always dis-
abled (off). For voltage measurements, guard is enabled or
disabled from the Configure Voltage menu structure as ex-
plained in paragraph 2.5.2.
The INPUT triax connector is also used for the Force Voltage
Measure Current configuration. This configuration utilizes
the V-source to make resistance measurements (see para-
graph 2.4.2) and current measurements (see paragraph
2.4.3).
Use the following rules to navigate through the menu struc-
ture:
1. The top level of the Main Menu is accessed by pressing
the MENU key. A Configuration menu is accessed by
pressing CONFIG and then the desired function (V, I,
etc.) or operation (TRIG, STORE, etc.).
2. A menu item is selected by placing the cursor on it and
pressing ENTER. Cursor position is denoted by the
blinking menu item or parameter. The cursor keys (
and
) control cursor position.
3. A displayed arrow (
and
) on the bottom line indi-
cates that there are one or more additional items (mes-
sages) to select from. Use the appropriate cursor key to
display them.
4. A numeric parameter is keyed in by placing the cursor
on the digit to be changed and using the RANGE
▲
or
▼
key to increment or decrement the digit.
5. A change is only executed when ENTER is pressed. En-
tering an invalid parameter generates an error and the
entry is ignored.
6. The EXIT key is used to back out of the menu structure.
Any change that is not entered is cancelled when EXIT
is pressed. The EXIT key has additional actions and are
summarized in Table 2-7.
7. The VOLTAGE SOURCE
▼
and
▲
keys are used adjust
the V-Source value. The V-Source is decremented or in-
cremented by placing the cursor on the desired digit and
pressing
▼
or
▲
. With the cursor on the polarity sign,
pressing
▼
or
▲
toggles the polarity. Pressing CONFIG
and then
▼
or
▲
displays the CONFIGURE V-
SOURCE menu.
2.4
Connections — electrometer, high-
resistance meter, and V-source
The following information provides basic information on
electrometer, high-resistance meter, and V-source connec-
tions. Also covered is the use of low-noise cables and shield-
Table 2-7
EXIT key actions
Condition
EXIT key action
Temporary message displayed
(e.g., TRIGGERS HALTED)
INFO message displayed
Reading display hold
Scanning
Data storage
Cancels display of temporary message.
Cancels INFO message, returns to menu or normal reading display.
Cancels reading display hold, resumes normal reading display.
Disables scanning. Also stops data storage if enabled.
Stops data storage. Temporary message STORAGE INTERRUPTED
is displayed.
