Kikusui TOS9200, Руководство по эксплуатации

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TOS9200/9201 Basic Operations 3-15
Setting LO W/GU ARD f or the GND
Y ou can select either of the follo wing tw o measurement modes;
the LO W mode that the GND is connected to the tester’ s LO W terminal,
the GU ARD mode that the GND is used as guard.
In both modes, the tester detects the current fl o wing into the LO W terminal from the
HIGH V OL T A GE terminal via the DUT . In the LO W mode, the LO W terminal is
connected to the chassis. This leads to the problem that the stray capacity and insu -
lation resistance existing between the test leadwire or jigs and the earth are included
in the measurement. Nonetheless, the GND mode ensures safe testing, as it does not
short-circuit the ammeter.
In the GUARD mode, on the other hand, only the current
fl owing into the LOW ter-
minal from the HIGH VOLTAGE terminal via the DUT is measured, and the in fl u-
ence of the stray capacity and insulation resistance existing between the test
leadwire or jigs and the earth is eliminated. For this reason, the GUARD mode is
effective in measurements that require high sensitivity and high accuracy. At the
same time, however, the ammeter can be short-circuited, posing a grave danger if
the LOW terminal and the chassis are short-circuited when part of the DUT is con-
nected to an earth ground. If it is possible that the DUTs and jigs are grounded,
select the LOW mode.
To switch between the two modes, use the SHIFT + F3 keys, regardless of the loca-
tion of the cursor. Each time the SHIFT + F3 keys are pressed, LOW and GUARD
alternate.
Using the keys, move the cursor to the right of GND; settings can then be
made using the rotary knob.
Turn the rotary knob clockwise : GUARD
Turn the rotary knob counterclockwise : LOW
When LOW is selected, the LED to the left of the LOW terminal lights up.
ACW2 ACW2
START : 10% V RANGE : AUTO
RISE : 0.1s (– – – V/s) RESPONSE : SLOW
FALL : 0.0s (– – – V/s) GND : LOW
F1 F2 F3 F4 F5
SHIFT
V RANGE
RES-
PONSE
GND
LED lights up