Megger MFT-X1 - Instrument Controls

14. Earth Loop Impedance testing – TrueLoop™ ..............................................................................61
14.1 General .....................................................................................................................................................61
14.1.1 About Loop Impedance tests ..................................................................................................................61
14.1.2 Using the Confidence Meter™ ............................................................................................................... 62
14.2 Loop test options .....................................................................................................................................63
14.2.1 Hot key 1 – Types of loop test ................................................................................................................63
14.2.2 Hot key 2 – No RCD, RCD or EV RDC options .........................................................................................63
14.2.3 Hot key 3 – No RCD, RCD or EV RDC options .........................................................................................64
14.2.4 Hot key 4 – 2 wire, 2 wire HR and 3 wire methods .................................................................................64
14.2.5 Hot key 5 – test-lead connections ...........................................................................................................64
14.2.6 Test inhibit .............................................................................................................................................65
14.3 Hot keys for Loop Impedance tests ........................................................................................................65
14.4 Test-lead null ............................................................................................................................................ 65
14.5 Loop test recommendation table ........................................................................................................... 66
14.6 Measuring Loop Impedance – No RCD in circuit ...................................................................................66
14.7 Measuring Loop Impedance (Zs) with RCD protection in circuit .......................................................... 68
14.8 Measuring EV charger Loop Impedance ................................................................................................69
14.9 Zmax – to find the highest Loop Impedance for a circuit .....................................................................69
14.10 Zref – making and using the reference impedance for R1+R2 and Vdrop calculations ...................71
14.11 R1 + R2 mode .........................................................................................................................................73
14.12 Setting i-vdrop for volts drop measurements ......................................................................................74
14.12.1 Volt drop ..............................................................................................................................................74
14.12.2 Setting Zref ..........................................................................................................................................74
14.12.3 Setting i-vdrop .....................................................................................................................................75
14.12.4 Making a Volt drop measurement ........................................................................................................76
15. Instrument settings navigation .................................................................................................... 77
15.1 Settings screen navigation ...................................................................................................................... 77
15.2 Hot keys in settings mode .......................................................................................................................77
15.3 Entering and leaving settings mode ......................................................................................................78
15.4 Selecting a settings page ........................................................................................................................78
15.5 General settings .......................................................................................................................................78
15.5.1 Screen brightness ................................................................................................................................... 79
15.5.2 Backlight timer .......................................................................................................................................79
15.5.3 Contrast mode .......................................................................................................................................79
15.5.4 Setting the date .....................................................................................................................................79
15.5.5 Setting the time .....................................................................................................................................80
15.5.6 Key press beep ....................................................................................................................................... 80
15.5.7 Results beep ..........................................................................................................................................80
15.5.8 Sleep timer .............................................................................................................................................81
15.5.9 Language ...............................................................................................................................................81
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