Hioki DSM-8542, Instruction Manual, Page: 46 / 140

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• Power source noise filter
Noise of measuring voltage output greatly affects the measurement accuracy in
measurement of samples which have a high electrostatic capacity such as capacitors.
For this reason, the meter is equipped with a filter to reduce noise of measuring voltage
output.
In regular measurement, stable measurement is possible by turning a filter on. The
condition in which the filter is turned on is called the “low-noise mode.”
The low-noise mode enables stable measurement with less noise. However, one
disadvantage with this mode is that the changeover speed of measuring voltage becomes
slow depending on the filter response time.
Select the high-speed changeover mode with the filter turned off in measurement that
requires fast changeover of measuring voltage.
The low-noise mode with the filter turned on is set during preshipment inspection of the
meter at the HIOKI factory.
5.2.5 Setting
measuring range
The meter consists of a high-sensitivity current measuring unit and a measuring voltage
output unit and calculates an insulation resistance value based on a measured current
value and measuring voltage.
The measuring range of the meter indicates a current measuring range of the current
measuring unit, rather than a resistance measuring range. There are eight current
measuring ranges for the current measuring unit. The full-scale sensitivity of each
range is decided by the integral time setting.
The full-scale current value is expressed roughly by the following formula. (10mA is
maximum)
I
FS
= 3 x 10
-( 4 + R )
/T(mA)
where I
FS:
full-scale current value, R: range and T: integral time
Table 5.6 shows the relationship between typical integral times and full-scale sensitivities
of the various ranges.
Range changeover enables setting of auto changeover and fixed range.
(1) Keying
(a) Press the [F5] PSET key to set the Measuring Condition Setting mode.
(b) Move to “RANGE:” operating the cursor moving keys [
◄
], [
►
], [
▲
] and [
▼
].
(c) Set “AUTO/HOLD” by operating the [F4] AUTO and [F5] HOLD keys.
(d) In case “HOLD” is set, operate the [F2] DOWN and [F3] UP keys and set a
range.
“AUTO” sets auto changeover and “HOLD,” a fixed range.
“DOWN” changes the range toward low current sensitivity and “UP,” toward
high current sensitivity.