Unitest Telaris 0100, Инструкция по эксплуатации

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5.4 Low-Ohm Resistance Measurement
The measurement is used to check protective earth
conductors, grounding conductors, and equipoten-
tial bonding conductors for low-impedance conti-
nuity. The resistance is determined by current/vol-
tage measurement.
Prior to any Resistance measurement, it must
be guaranteed that no installation parts to be
tested are live.
If an external voltage is present, the instrument
displays „Uext" after the „Start" key has been
pressed. The Low-Ohm resistance measure-
ment is then blocked. The symbol „Uext" (5)
appears if a second measurement is started
without foreign voltage present.
Prior to any resistance measurement it is pos-
sible to compensate test lead resistance (plea-
se refer to chapter 5.4.1).
"
Connect red test lead (equipped with individual
plugs) to the TELARIS 0100.
" Plug test probes or crocodile clips onto the test
leads and connect the test leads to the
EUT.
" Set measurement range selection switch (24) to
„LOW-
Ω
" measurement range.
"
Now connect test leads to EUT:
"
Press key „Start" (25).
"
Read measurement value on display.
If „>19,99
Ω
" appears on the display, the resi-
stance is higher than 19.99 Ohm.
The polarity of the test current applied may in-
fluence the measurement result by means of
galvanic elements within the EUT. For this rea-
son always repeat the measurement with re-
versed polarity to compare the measurement
results.
The measurement results can be falsified by
parallel connection of impedances of additio-
nal service circuits or by compensating cur-
rents.
Possibility to store the measurement result by
pressing key „Store" (26).
5.4.1 Compensating Test Lead Resistance
TELARIS 0100 allows for compensation of test lead
resistance. The test lead resistance may amount up
to 1,99
Ω
. Proceed as follows:
"
Connect three pole test leads to the TELARIS
0100.
"
Short-circuit both test leads U+ and U-.
"
Set measurement range selection switch (24) to
„LOW-
Ω
" measurement range.
" Press key „COMP" (31).
If the test lead resistance has been properly
compensated for, the symbol „COMP" (15) and
the value 0.00 Ohm appears on the display.
Furthermore, an acoustic signal isaudible. If
the test lead resistance exceeds 1,99 Ohm, the
symbol „COMP" (15) blinks twice and the error
signal is audible.
The compensation value is maintained even
after switching the instrument off.
" To clear the compensation value, please press
the "COMP” key (31) again.
38
Low-Ohm Resistance Measurement (Continuity)