4. Press GO/STOP to start the test. In case no error conditions
occur, the instrument displays the message “Measuring…” as
shown in the screen to the side.
5. When measurement (with a fixed duration of 10s) is complete,
the instrument provides the values Ri (+) and Ri (-), respectively
the insulation resistance of the Positive and Negative poles of the
PV field being tested. If both results are higher than the minimum
limit set, the instrument displays the message “Outcome:OK”;
otherwise, it displays the message “Outcome: NO” as shown in
the screen to the side.
6. Press the SAVE key to store the test result in the instrument’s
memory (see § 7.2) or the ESC/MENU key to exit the screen
without saving and go back to the main measuring screen.
6.4.3. Measuring insulation – TIMER mode
1. Position the cursor onto MΩ by using the arrow keys (,) and
confirm with ENTER. The display shows the screen to the side.
2. Press the ENTER key, activate “Settings” and possibly change the
desired parameters (see § 5.4). The following parameters are
shown on the display:
Ins. Test selected test voltage (250, 500 or 1000VDC)
Ri min minimum limit threshold for insulation measurement
Mode measuring mode: TIMER
Vtest real applied test voltage
Ri (+) minimum insulation resistance between the Positive pole
and the earthing detected during the whole duration of measurement.
Test time test duration which can be set within a range of 10 ÷ 300s
key access to the second page with the measured values of VPN, VEP and
VEN voltages
3. Connect the instrument to the PV module/string being tested and then to possible unearthed
metal masses and to the main earth node of the system (see Fig. 11). In particular, connect the
positive output pole of the PV module/string and the metal masses to terminal P.
CAPTION:
E: Green cable
P: Red cable
N: Black cable
1. Unearthed PV
module/string
2. Main system
earthing
3. Unearthed metal mass
Fig. 11: Instrument connection for insulation measurement in TIMER mode
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