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TEST MODE SUMMARY
Press the 'MODE' button to cycle through and select the test mode.
Modes of test to be chosen from include an insulation resistance 'IR' test, a
polarization index 'PI' test, a step voltage 'SV' test, and a dielectric
discharge 'DD' test. If timers T1 and T2 are set, the instrument will
automatically calculate the dielectric absorption ratio 'DAR' of the
insulation. PI, DAR, and IR values are automatically stored and displayed if
the data is available, irrespective of the selected test mode. At the end of a
test the instrument can be made to display either the insulation
resistances, insulation currents, the filter setting, or ratios plus capacitance
Ω
measurements by using the '
/I' toggle button. See section '
for cycling through results and toggling units.
Hardware filter
The hardware noise current filter may be switched on or off before, but
not during, testing. Turning the hardware filter off may be beneficial for
short test durations and higher load capacitances providing there is little
noise current.
This feature may be set in any mode, i.e. IR, PI, SV , or DD. Press and hold
the Fn button while repeatedly pressing the
the filter options. Select FIL OFF for the fastest settling time, or FIL ON for
the default 4mA noise filter. Note that if FIL OFF is selected, the firmware
filtering option (refer to section "Insulation Resistance "IR" test") will be
disabled. This setting may not be adjusted during a test.
Insulation Resistance 'IR' test
This is the default mode in which the instrument powers up. This test
mode measures insulation resistance continuously at the selected voltage.
The test voltage may be varied during an 'IR' test by pressing the test
voltage
or
buttons. The test duration can be set using the 'main
timer'. The test will finish automatically after this time has elapsed. On test
Ω
/I button'
Ω
/I button to scroll through
completion, insulation capacitance and the time constant associated with it
is calculated and displayed.
Time Constant (TC) = R
If timers T1 and T2 are set, the instrument will calculate and display the
DAR value under the segment 'DAR'. On completion of the test, the
instrument will display the insulation resistance measured at these times
under the segment symbols 'T1' and 'T2'. If the test runs for longer than
10 minutes, the instrument will calculate the 'polarisation index'. This
value will be displayed under the display segment symbol 'PI'. On
completion of the test, the instrument will display the insulation resistance
recorded at 1 minute and 10 minutes under the segment symbols '1m' and
'10m'.
Ω
Pressing the '
/I' button toggles the display to show the insulation
resistances, insulation currents, the filter setting, DAR and PI ratios, and
capacitance. The resistances and currents will be displayed under the 'T1',
'T2', '1m' and '10m' segment headings, the ratios under the 'DAR' and 'PI'
segment headings. The capacitance reading is indicated by its units of
either 'nF' or 'µF'. Refer to section '
Firmware filtering
There is an option (in Insulation Resistance mode only) to switch in
firmware filtering to average out slow variations. The firmware filter time
constants are 10, 30, and 100 seconds. The additional firmware filter
setting may be adjusted before or during a test, unless the filter was set to
FIL OFF before the test started, in which case the additional firmware
filtering option will be unavailable during testing. If the additional
firmware filter is switched in during a test, then any subsequent PI, DAR,
or TC calculated results are regarded as invalid, and are consequently not
displayed. The resistances and currents at these times are still indicated in
the secondary displays should they be needed.
x C
ins
ins
Ω
/I button'.
15
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