NA3571 Digital earth resistance tester
Product introduction 
The Digital Earth Resistance Tester abandon the traditional hand generate working method, use advanced large scale integrated circuits, apply to DC / AC conversion technology, which combine the three terminal and four terminal measurement models into a new earth resistance measuring instrument.
Operation principle:
Transform DC into AC low frequency constant current by build-in DC / AC converter, then through the auxiliary earth electrode C and tested object E form a circuit, it will generate AC voltage drop on the measured object, through the auxiliary ground electrode P send into AC amplifier to magnify, and through the detector into the meter to display. By using the multiplying power, can get three different range: 0~2Ω, 0~20Ω, 0~200Ω.
This tester applies to measure ground resistance of various devices and low resistance conductor resistance in electricity, telecommunications, railways, telecommunications, mining and other sectors; This tester also can measure soil resistivity and ground voltage.
Also called name
Ground continuity tester, ground resistance tester, Medical Ground Resistance Tester, NA3571 Digital earth resistance tester
The Characteristics of the products
1.Adopt high strength aluminum alloy case, in order to prevent power frequency and radio frequency interference, it use phase-locked loop synchronously tracking detecting method, and also equip with switching capacity filter, that make the tester with high anti-jamming capability.
2.Adopt DC / AC conversion technology, change DC to AC low frequency constant current, in order to measure.
3.Allow the earth resistance changing between 0~2KΩ (RC) and 0~40KΩ (RP), it does not affect the measured result.
4.No need to regulate balance artificially, 3(1/2) bit LCD display, not only can measure the earth resistance, but also can measure low resistance conductor resistance, earth resistivity and AC earth voltage.
5.If measure the test loop fails, the meter shows "1", means overflow, that conform to the standard habit of measurement.
The parameters of the products 
1. Operation condition
Temperature:0℃~+45℃
Relative humidity: ≤85%RH
2. Measurement range and constant current value (Valid value)
  Resistance: 0~2Ω (10mA), 2~20Ω (10mA), 20~200Ω (1mA)
  Voltage: AC  0~30V
3. Measure accuracy and resolution
  Accuracy: 0~0.2Ω≤±3%±1d
  0.2Ω~200Ω≤±1.5%±1d
  1~30V≤±3%±1d
Resolution: 0.001Ω, 0.01Ω, 0.1Ω, 0.01V
4. Auxiliary grounding resistance and error caused by grounding voltage
·Allowed auxiliary grounding resistance RC( between C1 and C2)<1.8KΩ;
  RP( between P1 and P2)<40KΩ, Error ≤±5%
·Allowed grounding voltage ≤5V (power frequency valid value)  error ≤±5%
5. Power and power consumption
Max power consumption ≤2W
Power supply: 6.8V~9V (7 5#rechargeable battery group), external AC 220V power source.
Dimension: 220×200×105mm(LWH)
Weight:≤1.4kg
 
Product information
1, be sure to read this before using the manual, and follow the instructions steps accordingly.
2, do not use non-original accessories provided, to avoid danger.
3, test equipment must be grounded.
4, the operator must be familiar with the operating procedures of the tester before use.
5, do not adjust other button during the whole measurement process.
6, completed the test, make sure all in the reset mode before removing the wiring.
7, do not block slit or vents, ensuring the cooling effect of the instrument function well,.
8, avoided in the following environments:
(1) Avoid direct sunlight, rain or moisture;
(2) Keep away from fire and heat;
(3) Must shut down and remove the power cord before handling or maintenance.