1.1. Working principle

In this table, the traditional manual power generation mode is abandoned, and the advanced medium and large scale integrated circuit is adopted. The DC/AC transformation  technology  is  applied  to  combine  the  measuring  mode  of three-end  knob  and  four-end  knob  into  a  new  type  of  grounding  resistance measuring instrument.

The working principle is that the DC/AC converter converts DC into AC with low frequency constant current. The circuit consists of auxiliary grounding pole C and measured object E, and AC voltage drop is generated on the measured object. The circuit is sent to AC amplifier by auxiliary grounding pole P for amplification, and then sent to the watch head for display through detection. With the aid of multiplying power switch, three different quantity limit can be obtained: 0 ~ 2 Ω , 0 ~ 20 Ω , 0 ~ 200 Ω .

1.2. Scope of use

This table is suitable for measuring the grounding resistance of various devices and   the    conductor   resistance    of    low    resistance   in    power,    post   and telecommunications, railway, communication, mining and other departments. This table can also measure the soil resistivity and ground voltage.

1.3. Main features

(1) The structure adopts high strength aluminum alloy as the chassis. In order to prevent  power frequency  and  radio frequency  interference,  the circuit adopts phase-locked  loop  synchronous  tracking  detection  mode  and  equipped  with switching capacitor filter, so that the instrument has better anti-interference ability. (2) DC/AC conversion technology is adopted to convert DC into AC low-frequency constant current for easy measurement.

(3) allow auxiliary grounding resistance in 0 ~ 2 k Ω (RC), 0 ~ 40 k Ω (RP), don't affect the measurement result.

(4)  This  instrument  does  not  need  manual  adjustment  balance,  3(1/2)  LCD display, in addition to measuring the ground resistance, but also can measure the low resistance conductor resistance, soil resistivity and ac ground voltage.

(5)  If the test circuit is closed and the header shows " 1" for overflow, it is  in

accordance with the conventional measurement habit.

2.1. Conditions of use

Ambient temperature: 0℃ ~ +45℃ Relative humidity: ≤85%RH

2.2. Measuring range and constant current value (Root Mean Square) Resistance: 0 ~ 2 Ω (10 mA), 2 ~ 20 Ω (10mA), 20 ~ 200 Ω (1mA)

Voltage: AC 0 ~ 19.99V

2.3. Measurement accuracy and resolution Accuracy:

0~0.2Ω≤±3%±1d

0.2Ω~199.9Ω≤±1.5%±1d 1~ 19.99V≤±3%±1d

Resolution: 0.001Ω 、0.01Ω 、0. 1Ω 、0.01V

2.4. Auxiliary grounding resistance and measurement error caused by ground voltage

Auxiliary grounding resistance RC (between C1 and C2)

0～2Ω , 2～20Ω ≤1KΩ 20～200Ω ≤2KΩ

RP（between P1 and P2）<40KΩ    Error ≤±5%

Allowable ground voltage (power frequency effective value) ≤5V    Error ≤±5% 

2.5. Power supply and power consumption

Maximum power loss ≤2W

DC: 8* 1.5V(AA, R6) battery

Communication: 220V±10% / 50 Hz 2.6. Volume and weight

Size: 220 mm * 200 mm * 105 mm Weight: ≤1.4 kg