Hioki MEMORY HiCORDER 8855, Instruction Manual

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Safety Notes
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CAT I Secondary electrical circuits connected to an AC electrical
outlet through a transformer or similar device.
CAT II
Primary electrical circuits in equipment connected to an AC
electrical outlet by a power cord (portable tools, household
appliances, etc.)
CAT III Primary electrical circuits of heavy equipment (fixed
installations) connected directly to the distribution panel,
and feeders from the distribution panel to outlets.
CAT IV The circuit from the service drop to the service entrance,
and to the power meter and primary overcurrent protection
device (distribution panel).
f.s. (maximum display value or scale length)
The maximum displayable value or the full length of the scale.
This is usually the maximum value of the currently selected range.
rdg. (reading or displayed value)
The value currently being measured and indicated on the measuring
instrument.
dgt. (resolution)
The smallest displayable unit on a digital measuring instrument, i.e.,
the input value that causes the digital display to show a "1".
Measurement categories (Overvoltage categories)
This instrument complies with CAT II safety requirements.
To ensure safe operation of measurement instruments, IEC 61010 establishes
safety standards for various electrical environments, categorized as CAT I to
CAT IV, and called measurement categories. These are defined as follows.
Higher-numbered categories correspond to electrical environments with
greater momentary energy. So a measurement device designed for CAT III
environments can endure greater momentary energy than a device designed
for CAT II.
Using a measurement instrument in an environment designated with a
higher-numbered category than that for which the instrument is rated could
result in a severe accident, and must be carefully avoided.
Never use a CAT I measuring instrument in CAT II, III, or IV environments.
The measurement categories comply with the Overvoltage Categories of the
IEC60664 Standards.
Accuracy
We define measurement tolerances in terms of f.s. (full scale), rdg. (reading)
and dgt. (digit) values, with the following meanings: