LEM SATURN 100 PLUS Gebrauchsanleitung Seite 48

Information for the tester
Earth/Ground Resistance R
A
The sequence for determining earthing/grounding resistance corresponds to that of
the FI circuit breaker test with sonde. However, the test current is predetermined
for this function in terms of the range:
10 kΩ =
1 kΩ =
Ω
100 =
Ω
<15 =
Insulation Resistance R
ISO
The first measurement is a check whether the input voltage is less than 50 V AC.
This measurement is performed by ADC. The processor takes care of evaluation
and further processing. If the voltage is less than 50 V, measurement can be
started. All required switching operation are performed by relays controlled by the
processor. Selection of the pairs of lines to be measured is effected by means of
the rotary selector. The required measuring voltage of 500 V DC is obtained by
DC/DC conversion. Measuring voltage and measuring current are measured,
processed in the processor and displayed as the insulation resistance.
The range of the current-measuring resistor required for optimum display is
automatically set by the processor.
At the end of measurement, the voltage is switched off and any capacitance
discharged across the instrument's internal resistor.
Loop Resistance R (R )
LOOP S
The first measurement is a check whether the input voltage is between 101 V and
435 V.
If this condition is met, measurement is started. All switching operations are
performed by relays controlled by the processor. Selection of pairs of lines to be
measured is effected by means of the rotary selector.
In the L-PE position, both lines (L, N) are checked for voltage, and the load is
applied to the larger of the two input voltages measured. Subsequently there is an
alternation of one loaded and one unloaded cycle (lowering of voltage). From the
difference of the two measured voltages, the processor computes and displays the
loop resistance.
5 mA
50 mA
500 mA
1 A
46