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10 TEGAM WAY • GENEVA, OHIO 44041 • 440-466-6100 • FAX 440-466-6110 • [email protected]
INSTRUMENT DESCRIPTION
SECTION 1
INSTRUMENT DESCRIPTION
1.1 Introduction
The TEGAM Model R1L-E2A is an intrinsically safe portable
bond meter/microohmmeter designed to measure low values
of resistance, from 1 µΩ to 20 Ω. A four point measurement
method is utilized in order to eliminate any errors caused by
the resistance of the measuring leads. Two leads are used to
pass a constant regulated current through the resistance
under test, and two leads are used to measure the resulting
voltage drop across the resistance under test. The R1L-E2A
then uses Ohm’s law to calculate the resistance and displays
the value digitally on a liquid crystal display (LCD). The R1L-
E2A cycles the current ON and OFF during the measurement.
During the OFF state, thermal and offset voltages, occurring
in the voltage measurement chain, are stored, and then used
as a correction during the ON current time.
The current used for the measurement is well regulated to be
constant over large changes in the unknown resistance
and/or the resistance of the test leads. If the resistance under
test becomes too high on a given range, the display shows a
“1” followed by three blanks.
1.2 Performance Characteristics
The R1L-E2A has five resistance ranges, with test current,
resolution, and scale as shown below in Table 1.
Range
Full Scale
(Ω)
Resolution
(Ω)
Test Current
Peak (A)
1
1.999 m
1 µ
1.3
2
19.99 m
10 µ
130 m
3
199.9 m
100 µ
13 m
4
1.999
1 m
1.3 m
5
19.99
10 m
0.13 m
Table 1: Range Specifications
Accuracy: All ranges: 0.1% of reading ± 2 counts.
