MI 3290 Earth Analyser
Technical specifications
140
15.9 Influence of the auxiliary electrodes
Definition of Rc, Rp and Ra:
Rc ..................................................... Impedance of auxiliary current probes (Rh + Re)
Rp ..................................................... Impedance of auxiliary potential probes (Rs + Res)
Ra ..................................................... Earth resistance
Measurement function ........................................ 3, 4 – pole, Selective (Iron, Flex Clamp),
Wenner and Schlumberger method,
HF Earth Resistance (25 kHz), Potential
Additional uncertainty if limit (Rh, Rs, Res, Re) or max. value are exceeded (whichever is lower).
Test frequency
Limit for Rh and Re
Limit for Rs and Res
max.
value
Additional
uncertainty
55 Hz … 164 Hz
> 300 Ω + (2 k * Ra)
> 300 Ω + (1 k * Ra)
50 k
(15 % of reading)
329 Hz … 659 Hz
> 250 Ω + (1 k * Ra)
> 250 Ω + (500 * Ra)
25 k
(15 % of reading)
1,31 kHz … 2,63 kHz
> 100 Ω + (500 * Ra)
> 50 Ω + (250 * Ra)
12,5 k
(15 % of reading)
3,29 kHz … 6,59 kHz
> 100 Ω + (250 * Ra)
> 50 Ω + (125 * Ra)
6,25 k
(15 % of reading)
13,1 kHz … 15,0 kHz
> 50 Ω + (150 * Ra)
> 50 Ω + (50 * Ra)
3,1 k
(15 % of reading)
25,0 kHz
> 250 Ω + (500 * Ra)
/
2 k
(15 % of reading)
If the auxiliary probes limit is exceeded by an additional 50 % then the measuring range of the
instrument is exceeded.
Standard uncertainty
Additional error
≤ Limit
≤ Limit + 50%
or max. value
Impedance of auxiliary Rc and potential Rp probes
The measuring range of the instrument is exceeded.
Measurement could not be started or displayed!
Notes:
High impedance of auxiliary current or potential probes icon.
High impedance of auxiliary current and potential probes.
High impedance of auxiliary current probe Rc.
High impedance of auxiliary potential probe Rp.
