Manual

Gossen Metrawatt GmbH 77
17 Measuring Low-Value Resistance of up to 200  (Protective Conductor and Equipotential Bonding Conductor)
According to the regulations, the measurement of low-value resis-
tance at protective conductors, earth conductors or bonding con-
ductors must be performed with (automatic) polarity reversal of
the test voltage, or with current flow in one (+ pole to PE) and then
the other direction (– pole to PE).
Attention!
!
Low-resistance may only be measured at voltage-free
objects.
Select Measuring Function
Connection
via 2-pole adapter only!
Set Parameters
❏ ROFFSET ON/OFF
– Compensation for Measurement Cables up to 10 
If measurement cables or extension cables are used, their resis-
tance can be automatically subtracted from the measurement
results. Proceed as follows:
➭ Switch R
OFFSET from OFF to ON. Roffset = 0.00  appears in the
footer.
➭ Select a polarity option or automatic polarity reversal.
➭ Short-circuit the end of the measurement extension cable with
the second test probe at the instrument.
➭ Start measurement of offset resistance with I
N
.
First of all, an intermittent acoustic warning is
generated and a blinking message appears, in
order to prevent inadvertent deletion of a previ-
ously saved offset value.
➭ Start offset measurement by pressing
the triggering key once again or abort
offset measurement by pressing the ON/
START ▼
key (in this case = ESC ).
Note
If offset measurement is stopped upon appearance of a
pop-up error window indicating Roffset > 10  or a differ-
ence between RLO+ and RLO– of greater than 10%, the last
measured offset value is retained. Inadvertent deletion of
a previously ascertained offset value is thus practically
ruled out. The respectively smaller value is otherwise
stored to memory as an offset value. The maximum offset
value is 10.0 . Negative resistances may result due to
the offset value.
Measuring ROFFSET
The ROFFSET x.xx  mes-
sage now appears in the footer at the display, where x.xx can be
a value between 0.00 and 10.0. This value is subtracted from
the actual measuring results for all subsequent R
LO
measure-
ments, if the R
OFFSET ON/OFF key has been set to ON.
R
OFFSET must be redetermined in the following cases:
• After switching to a different polarity option
• After switching from ON to OFF and back again
The offset value can be deliberately deleted by switching ROFFSET
from OFF to ON.
Note
Only use this function when performing measurements
with extension cables.
When different extension cables are used, the above
described procedure must always be repeated.
❏ Type / Polarity
The direction in which current flows can be selected here.
❏ Limits – Setting the Limit Value
The limit value for resistance can be set as desired. If measured
values occur which are above this limit value, the red UL/RL LED
lights up. Limit values can be selected within a range of 0.10  to
10.0  (editable). The limit value is displayed above the measured
value.
R
LO
ROFFSET: ON  OFF
Polarity: +/– to PE
Polarity: +/– to PE
with ramp sequence
Limit Value:
R
LO
> Limit Value
U
L
 R
L