GMC-I Messtechnik GmbH
35
q
Pole Selection Report Entry
The poles between which testing takes place can only be entered
here for reporting purposes. The entry itself has no influence on
the actual polarity of the test probes or the pole selection.
q
Limits – Setting the Limit Value
The limit value for insulation resistance can be set as desired. If
measurement values occur which are below this limit value, the
red U
L
/R
L
LED lights up. A selection of limit values ranging from
0.5 M
to 10 M
is available. The limit value is displayed above
the measured value.
Start Measurement – Rising Test Voltage (Ramp Function)
Press briefly
Note
When selecting „Semiautomatic polarity reversal“ (see
section 5.8) the symbol for semiautomatic polarity rever-
sal is shown instead of the ramp.
Start Measurement – Constant Test Voltage
Press and hold for
permanent measure-
ment
Note
The instrument’s rechargeable batteries are exposed to
excessive stress during insulation resistance measure-
ment. When using the “constant test voltage” function,
only press and hold the Start
t
key until the display has
become stable.
Special Condition for Insulation Resistance Measurement
Attention!
!
Insulation resistance can only be measured at
voltage-free objects.
If measured insulation resistance is less than the selected limit
value, the U
L
/R
L
LED lights up.
If an interference voltage of
25 V is present within the system,
insulation resistance is not measured. The MAINS/NETZ LED
lights up
and the message „Interference voltage present“ pops
up.
All conductors (L1, L2, L3 and N) must be tested against PE!
Attention!
!
Do not touch the instrument’s terminal contacts during
insulation resistance measurements!
If nothing has been connected to the terminal contacts, or if a
resistive load component has been connected for measurement,
your body would be exposed to a current of approx. 1 mA at a
voltage of 1000 V.
The resulting electrical shock is not life endangering. However, the
noticeable shock may lead to injury (e.g. resulting from a startled
reaction etc.).
Discharging the Device Under Test
Attention!
!
If measurement is performed at a capacitive object
such as a long cable, it becomes charged with up to
approximately 1000 V!
Touching such objects is life endangering!
When an insulation resistance measurement has been performed
on a capacitive object, it is automatically discharged by the
instrument after measurement has been completed. Therefore,
contact between the object and the instrument may not be inter-
rupted. The falling voltage value can be observed at the U display.
Do not disconnect the DUT until less than 10 V is displayed for U!
Evaluation of Measurement Values
The instrument’s measuring error must be taken into consider-
ation in order to assure that the limit values set forth in DIN VDE
regulations are not fallen short of. The required minimum display
values for insulation resistance can be determined with the help of
Table 3 on page 57. These values take maximum device error into
consideration (under nominal conditions of use). Intermediate val-
ues can be interpolated.
