46
R
H
and/or R
S
≤
20k
Ω
R
H
/R
E
and/or R
S
/R
E
≤
5000
Measurement freq. btw 41 and 300 Hz
± (5% + 2pt)
R
H
and/or R
S
≤
100k
Ω
R
H
/R
E
and/or R
S
/R
E
≤
20000
Measurement freq. btw 41 and 150 Hz
± (20% + 3pt)
Operating error
(1)
R
H
and/or R
S
≤
20k
Ω
R
H
/R
E
and/or R
S
/R
E
≤
1000
Measurement freq. btw 300 and 500 Hz
± (10% + 1pt)
Resistance of rods R
H
and R
S
Measurement range
0.01 – 9.99
Ω
10.0 – 99.9
Ω
100 - 999
Ω
1.00 – 9.99k
Ω
10 – 99.9k
Ω
Resolution
0.01
Ω
0.1
Ω
1
Ω
10
Ω
100
Ω
Intrinsic error
± (10% + 2pt) at 128 Hz
(1)
with spurious voltages
≤
60V
peak
and difference between measurement frequency and spurious
signal frequency > 0.2 x measurement frequency.
4.4 COUPLING MEASUREMENT (3-pole measurement)
This measurement is performed on the 3-pole position of the switch and in MANUAL mode only.
The earth coupling value is calculated using 3 successive earth resistance measurements :
- the first 2 measurements are two 3-pole classic measurements (see §4.3); these give
results R
1
and R
2
,
- the third measurement is a 2-pole measurement which gives the result R
1-2
.
Once the 3 measurements have been performed, the instrument automatically calculates the coupling
resistance R
C
as follows :
R
C
= (R
1
+ R
2
- R
1-2
) / 2
As well as the coupling factors C
1
and C
2
defined by :
C
1
= R
C
/ R
1
and C
2
= R
C
/ R
2
and the resistances R
A
and R
B
defined by :
R
A
= R
1
- R
C
and R
B
= R
2
- R
C
4.4.1
CONNECTIONS :
See above, §4.3.1.
4.4.2
PRE-MEASUREMENT SETTINGS
Configure the instrument for an EARTH COUPLING measurement:
- set the rotary switch to the 3-pole position,
- using the
CONFIG
DISTANCE
CONFIG
CONFIG
DISTANCE
key, select the MANUAL mode, then EARTH COUPLING.
Once again, using the
CONFIG
DISTANCE
CONFIG
CONFIG
DISTANCE
key, you can then:
- select the measurement frequency (41, 55, 92, 110, 119, 128, 476 Hz, or USr
(1)
),
- select the voltage applied (16 or 32 V).
(1)
The frequency "USr" is defined by the user for between 41 and 512 Hz using the
keys.