Measurement Functions; Ac / Dc Voltage; Insulation Measurements - Chauvin Arnoux C.A 6545 Notice De Fonctionnement

3. MEASUREMENT FUNCTIONS

3.1

AC / DC voltage

Any rotation of the switch on an insulation position sets the unit to automatic AC / DC voltage
measurement. The voltage is measured continuously and indicated on the small display.
The start of the insulation measurements is inhibited if an excessively high external voltage is present
on the terminals, before pressing START. Also, if an excessively high parasite voltage is detected during
these measurements, they are automatically stopped and the voltage is indicated (see § 3.2).
Switching between the AC and DC modes is automatic and the measurement is performed in RMS
values in AC.
3.2

Insulation measurements

As soon as the switch is rotated to an insulation position, the main display indicates "- - - - MΩ Ω Ω Ω Ω ", and the
small display indicates the voltage present on the + et – terminals of the unit.
! If, when the START key is pressed, the external voltage present at the terminals of the unit is higher
than the value defined by the relation above, the insulation measurement is not triggered and a series of
buzzes (beep, beep, beep...) is transmitted with flashing of the
returns to automatic voltage measurement.
with:
- Upeak : external peak voltage or DC present at unit terminals
- dISt : cœfficient defined in the set-up menu (adjustable to 0.03 – 0.10 – 0.20 – default value: 0.03)
- Un: test voltage chosen for insulation measurement
If the external voltage at the terminals of the unit is less than the value defined previously, the insulation
measurement is authorised.
Pressing the START key immediately triggers the measurement. The value of the measurement is
displayed on the main digital display and on the bargraph.
An audio warning is transmitted every 10 seconds to indicate that a measurement is in progress.
!
If the voltage generated might be dangerous (> 120 V), the
! If, during the insulation measurements, an external voltage higher than the value defined by the
relation below is detected, the measurement stops as long as the external voltage remains at the terminals
of the unit. The symbol flashes and the external voltage value is displayed on the small digital
!
display.
Note: Adjustment of the dISt factor optimises the measurement build-up time.
If there is no parasite voltage present, the dISt factor may be adjusted to the minimum value to obtain a
build-up time for the minimum measurement.
! If a significant parasite voltage is present, the dISt factor may be increased so that the measurement
is not interrupted by the appearance of a negative alternation during the generation of the test voltage,
which is the same as optimising the measurement build-up time in the presence of the parasite voltage.
!
U peak ≥ dISt x Un
U peak > (dISt + 1,05) Un
40
symbol for 2 seconds, then the unit
symbol is displayed.