Front Panel Operation
2-49
While in the multiple (NEXT) display state, you can tempo-
rarily display the voltage source value by pressing the
▲
or
▼
key. The voltage source value will appear on the second-
ary display for three seconds, unless an editing operation is
performed (see Adjusting Voltage Source Value).
Selecting voltage source range
NOTE
The voltage source range cannot be
changed while in Auto V-Source Ohms
(see “Auto V-Source” in paragraph 2.7).
With the voltage source value displayed, the position of the
decimal point denotes the currently selected range. For ex-
ample, a reading of 000.000V is 0V on the 100V range,
while a reading of 0000.00V is 0V on the 1000V range. The
RANGE option of the CONFIG V-SOURCE menu is used to
change the V-Source range and is summarized in Table 2-15.
1. From the CONFIG V-SOURCE menu, select RANGE
to display the range options (±100V or ±1000V). Note
that the 100V range provides better resolution; 5mV vs.
50mV for the 1000V range.
2. Place the cursor on the desired range and press ENTER.
3. Use the EXIT key to back out of the menu structure.
Adjusting voltage source value
NOTE
The voltage source value cannot be
changed while in Auto V-Source Ohms
(see “Auto V-Source” in paragraph 2.7).
The voltage source value can be changed
while in operate. While in operate, the out-
put voltage will immediately update to re-
flect the displayed value.
1. Select the voltage source edit mode by pressing the
▲
,
▼
,
or
key. The EDIT annunciator turns on and
the cursor position for the voltage source value is denot-
ed by the flashing digit. Note that the voltage source edit
mode will be cancelled if no edit operations are per-
formed within any three second period.
2. Using the keys, place the cursor on the digit to be
changed use the
▲
or
▼
key to increment or decrement
the value.
3. Polarity changes can be made in two ways:
• Increment or decrement the reading past 0V to change
polarity.
• Place the cursor on the polarity sign (+ or -) and press
▲
or
▼
to toggle polarity.
4. When finished, the voltage source edit mode will cancel
(EDIT annunciator off) after three seconds.
2.9.3 Voltage and current limit
The V-Source has a 1mA current limit for the 1000V range,
a 10mA limit for the 100V range, and an adjustable voltage
limit. If the current limit is reached, the VOLTAGE
SOURCE OPERATE indicator flashes. While in current lim-
it, the programmed voltage value is not being sourced. For
example, assume the voltage source is programmed to source
200V to a 100k
Ω
load. In this situation, current limit occurs
at approximately 100V (100k
Ω
×
1mA = 100V). Thus, the
voltage source will only output 100V.
A resistive current limit is also available for the V-Source.
When selected, a 20M
Ω
resistor is placed in series with the
V-Source HI lead. This allows current to be limited. For ex-
ample, with a programmed voltage of 100V, current will be
limited to 5µA (100V/20M
Ω
= 5µA).
Setting a voltage limit
NOTE
While in Auto V-Source Ohms, the voltage
limit of the V-Source can only be set to a
value that is >400V (see “Auto V-Source”
in paragraph 2.7).
The V-Source can be set to a maximum absolute value of
voltage that can be sourced. For example, setting a value of
30V limits the voltage output from -30V to +30V. The V-
LIMIT option of the CONFigure V-SOURCE menu is used
to set the V-Source voltage limit and is summarized in Table
2-15.
1. From the CONFigure V-SOURCE menu, select V-LIM-
IT to display the voltage limit selections:
CONTROL — Use this selection to enable (ON) or dis-
able (OFF) the voltage limit. When enabled, the V-
Source will be limited to the specified voltage limit val-
ue (see LIMIT VALUE).
LIMIT VALUE — Use this selection to set the voltage
limit using the
▲
,
▼
,
and
keys. Make sure to
press ENTER after changing the value.
2. Use the EXIT key to back out of the menu structure.
Selecting resistive current limit
Selecting the resistive current limit places a 20M
Ω
resistor in
series with the HI lead of the V-Source. The RESISTIVE
LIMIT option of the CONFIGURE V-SOURCE menu is
