User Manual

GMC-I Messtechnik GmbH 35
12 Measuring Low-Value Resistance up to 200 Ohm
(protective conductor and equipotential bonding
conductor)
According to the regulations, the measurement of low-value resis-
tance at protective conductors, earth conductors and bonding
conductors must be performed with (automatic) polarity reversal
of the test voltage, or with current flow in one direction (+ pole to
PE) and then the other (– pole an PE).
Attention!
!
Low-resistance may only be measured at voltage-free
objects.
Select the Measuring Function
Connection
2-pole
Set Parameters
Compensation for Measurement Cables up to 10 Ω
If measurement cables or extension cables are used, their resis-
tance can be deducted automatically from the measurement
results.
Proceed as follows:
Measuring ROFFSET
➭ Select a polarity option or automatic polarity reversal.
➭ Open the OFFSET menu by pressing I
∆N
.
➭ Using the PRO-Schuko measuring adapter (Z503K):
Short circuit the L and N contacts at the test plug by inserting
it into the short-circuiting jumper (PRO-JUMPER, Z503J).
➭ Using the KS-PROFITEST INTRO (Z503L) or Z550A:
Short circuit the test probes of the connected, and if applica-
ble extended, test leads by inserting the test probes into the
short-circuiting jumper (PRO-JUMPER, Z503J).
➭ Start measurement of offset resistance with I
∆ N
or CAL .
Note
If offset measurement is stopped upon appearance of a
pop-up error window (Roffset > 10 Ω or difference
between RLO+ and RLO– 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 Ω. Negative resistances may result due to
the offset value.
The ROFFSET x.xx Ω mes-
sage now appears in the
footer at the display,
where x.xx is a value
between 0.00 and
10.0 Ω. This value will
now be deducted from
the actual measurement
value for all subsequent
R
LO
measurements.
When switching
amongst polarity
options, ROFFSET is reset
to 0.00 Ω and must be
determined again.
Note
Use this function in general for all measurement cables.
Whenever different extension and measurement and
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 LIMIT LED
lights up. Limit values can be selected within a range of 0.10 Ω to
10.0 Ω (editable). The limit value is displayed above the measured
value.
R
LO
Polarity: ± to PE
Limit Value:
R
LO
> Limit Value
LIMIT