ES51998(60000counts)
DMM Analog front end/Insulation
Before measure insulation resistance, it is necessary to measure VDUT. If VDUT is too high,
the resistance measurement should be forbidden. The insulation V mode is implemented by
the same configuration with Voltage mode. The k factor of diagram is depended on the
voltage range. During insulation V mode, an external fast discharging path should be
applied on the HV sourcing part to release the high voltage charge on the DUT if it is
capacitive load.
Range control for insulation V mode
Q2 Q1 Q0
Full Scale Range
60.000V
0
0
1
1
1
0
0
1
0
600.00V
1000.0V
Note: 600mV – 6V ranges are omitted.
Insulation R mode configuration
F3
F2
F1
F0
IRV
IRR
Measurement mode
Read data bytes
1
1
1
1
0
1
Insulation R mode
D0(0:18)
Insulation R mode
MCU control
HV(25V ~ 1000V)
PTC
10MΩ
VD1
VA
ADC
IRVH0
IRVH1
VA = VD1 / RA * (10M+RA)
IRX = VD2 / RB = VB / RB
RX = (VA-VB) / IRX
MCU control
5.6KΩ
56KΩ
Rx
IRX
RA
VB
VD2
100kΩ
ADC
RB
Q1
Test mode
360kΩ
36kΩ
3.6kΩ
360Ω
IRR1
IRR5
IRR4
IRR3
IRR2
MCU control
Note: ADC full scale is 600mV typically.
ver. 1.7
25
12/01/12
CYRUSTEK [ Cyrustek corporation ]
