Preset - Keithley 486 Instruction Manual

SECTION 3
Front Panel Opemticm
Figure 3-8.
v-source Adjust
The cursor is indicated by the flashing digit. Jf an ad-
just action does not occur in three seconds, the cursor
will disable.
2. Select the appropriate v-source range.
The position of the decimal point in the displayed V-
Source reading denotes the selected range. For ex-
ample, a reading of OO.OOOV is OV on the 50V range,
while a reading of OCO.OOV is OV on the 500V range.
Ifonthe50Vrange,the500Vrangecanbeselectedby
pressing 4 until the displayed range changes. Con-
versely, to select the 50V range, press b until the
range change occurs.
3. Position the cursor on the digit to be adjusted.
The position of the cursor is controlled by the 4 and
b keys. Each press of the 4 key moves the cursor to
the next more significant digit. Each press of the b
key, moves the cursor to the next less significant
digit.
4. Adjust the voltage source 1eveL
The rotary knob is used to adjust the voltage source
level. Turning the knob clockwise increases the volt-
age level at the cursor position, and conversely, tom-
ing it counter-clockwise decreases the voltage level.
Cursor position determines how much the dis-
played value changes with each detent turn of the
knob. For example, with the cursor on the tenths
digit of the displayed value, each detent turn of the
knob will increase or decrease the value by 1 /lO volt
(10omv).
NOTE: For best accuracy, use the 5OV range to source
zk50.5v
or less.
Quick Zero
The Quick zero feature allows you to set the voltage
source of the Model 487 to OV with two key presses;
SHIFTand4or~key. Thevoltagesourcewillnot change
ranges. For example, with the voltage source level cur-
rently set to 100.5OV (5OOV range), pressing SHIFT and
the+ (or4 ) will set the voltage source to OV on the 500V
range (OOO.OOv). To return to the previously set voltage
source level, simply press SHIFT and w (or 4 ) again
3.6.3
Preset
PRESET
El
OHMS
(VA)
preset allows the V-Source to be adjusted to a predeter-
mined level at
the
touch of a single key. This feature
eliminates the tedious task of manually adjusting the V-
Source to a frequently used level.
Perform the following steps to preset a V-Source level:
1. Enable preset by pressing PRESET. The PRESET in-
dicator will turn on.
2. Adjust the V-Source to the desired range and level
using the
4
and b keys, and rotary knob as previ-
ously explained.
3. Disable preset by again pressing PRESET. The volt-
;a;,;urce will return to the level it was previously
Whenever preset is enabled, V-Source will adjust to the
value set in step 2.
NOTES:
1. A preset V-Source level can be saved as the default
condition (see paragraph 3.8.6).
2. A preset V-Source value of OO.COOV is the factory de-
fault condition.
3. With the V-Source in operate, the output will imme-
diately update to whatever voltage value is dis-
played (unless I-limit occurs).
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