Manual

24 Gossen Metrawatt GmbH
8 Measurements
8.1 Enabling Parameter Changes
If password protection has been set up (see section 6.7), the
password has to be entered for each of the following measure-
ments in order to change the parameters:
• RISO: Changes to test voltage
•m/4: Changes to test current
As soon as you attempt to change the above mentioned parame-
ters with the help of the
 scroll keys, the Password menu
appears. Enter the current password as described in section 6.7
on page 13.
8.2 Insulation Resistance Measurement – RISO Function
(METRAHIT IM XTRA BT and METRAHIT IM E-DRIVE BT only)
Caution: High-Voltage!
Do not touch the conductive ends of the test probes when the
instrument has been activated for the measurement of insulation
resistance.
You may otherwise be exposed to a current of 2.5 mA (lim-
ited in the measuring instrument), and although this is not
life endangering, the resulting electrical shock is quite dis-
cernible.
If, on the other hand, measurement is being performed on a
capacitive device under test, for example a cable, it may be
charged with up to approximately 1200 V. Touching the
device under test after measurement has been performed is life
endangering in this case!
Attention!
!
Insulation resistance may only be measured at voltage-
free devices!
Interference voltage detection is performed before and
during the measurement. If interference voltage Uext of
roughly  15 V AC or > 25 V DC is detected, visual and
acoustic warnings are generated. Measurement is also
disabled during pre-measurement testing. If interference
voltage is detected during measurement, automatic
switching to voltage measurement occurs and momen-
tarily measured voltage is displayed as Uext.
Attention!
!
The measurement cables may not come into contact
with each other during high-resistance insulation mea-
surements!
Note
The “ RISO ” or “ COIL ” switch position may only be used for
insulation resistance measurement and inter-turn short
circuit detection.
8.2.1 Preparing for Measurement
➭ Check the measurement cables:
Short circuit the test probes at the ends of the measurement ca-
bles before performing insulation resistance measurements with
the selector switch in the
 position, in order to make sure that
a value close to 0  is displayed at the instrument  In this way,
incorrect connection can be avoided and interrupted mea-
surement cables can be detected.
S– A
V
Temp
m/4
COIL
S+
00.00

Short circuit the measurement cables.
R
x
0V!
!

Temp
Uext
approx.
> 15 V
AC
> 25 V
DC
STOP!