13
Choice of measurement current: kW, 12 mA or 200 mA.
The high current (200 mA) can be used only to measure low resistances, up to 40
W
.
The low current (12 mA) is used to make measurements up to 400
W
.
The choice k
W
is used to make resistance measurements up to 400 k
W
.
SET UP
OFF
R
To correct for the resistance of the measurement leads (leads and probe tips or alligator clips), for measurements
at 12 and 200 mA (see §3.13).
Pressing the
TEST
button starts only one measurement (pulse mode).
3.3. RESISTANCE AND CONTINUITY MEASUREMENT
3.3.1. DESCRIPTION OF THE MEASUREMENT PRINCIPLE
For continuity measurements, the device generates a DC current of 200 or 12 mA, at the user’s discretion, between the
W
and
COM terminals. It then measures the voltage present between these two terminals and from it deduces the value of R = V/I.
For resistance measurements (current chosen = k
W
), the device generates a DC voltage between the
W
and COM terminals. It
then measures the current between these two terminals and from it deduces the value of R = V/I.
In the case of a measurement at high current (200 mA), at the end of one second, the device reverses the direction of the current
and makes another measurement for one second. The result displayed is the mean of these two measurements. It is possible to
make measurements with either the positive or the negative polarity of the current disabled.
For measurements at low current (12 mA or k
W
), the polarity is positive only.
3.3.2. MAKING A MEASUREMENT
To comply with standard IEC-61557, the measurements must be made at 200 mA. The reversal of the current serves to compen-
sate for any residual electromotive forces and, more important, to check that the continuity is in fact duplex.
When you make continuity measurements that are not contractual, prefer a current of 12 mA. Even though the results cannot be
regarded as those of a normative test, this significantly increases the life of the device between charges and forestalls untimely
tripping of the installations if there is a connection error.
The permanent mode is used to chain measurements without having to press the
TEST
button each time.
If the object to be measured is inductive, it is better to switch to pulse mode and make a measurement at positive polarity, then
a measurement at negative polarity, manually, in order to leave time for the measurement to settle.
The alarm, if activated, serves to inform the user, by an audible signal, that the measurement is below threshold, making it un-
necessary to look at the display unit to check this point.
Set the switch to
W
.
Use the leads to connect the device to be tested between the W and COM ter-
minals of the device. The object to be tested must not be live.
Pressing the
TEST
button starts the continuous measurement (permanent mode). To
stop it, you must press the
TEST
button again.
3.3.3. CONFIGURING THE MEASUREMENT
Before starting the measurement, you can configure it by modifying the parameters displayed:
