MEWOI MEWOI4000, Руководство пользователя, Страница: 10 / 20

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1. LCD 2. Button area 3. Rotary switch for selecting function
4. RS232 interface 5. Interface of testing wires
6. C(H) interface: Current electrode
7. P(S) interface: Voltage electrode
8. E interface: Earth electrode 9. Testing wires
10. Auxiliary grounding rod 11. Simple grounding wires
12. Testing probe 13. Safety alligator clip
V
．
Measuring Principle
1. Voltage to ground measurement adopts average value rectification method.
2. Earth resistance measurement with fall-of-potential method. AC constant
current
I (3mA Max, 820Hz) is applied between the measurement object E
(earth electrode) and C (current electrode), and finding out the potential
difference V between E and P (potential electrode).
Rx=V/I
3
．
Maximum Operating Error
：
Operating error(B) is an error obtained within the
rated operating conditions, and calculated with the intrinsic error(A), which is
an error of the instrument used, and the error(E) due to variations.
A
：
Intrinsic error
E1
：
Variation due to position change
E2
：
Variation due to power supply voltage
E3
：
Variation due to temperature change
E4
：
Variation due to interference voltage change