1. General Description

The TD8620 Handheld Digital Teslameter is a field-portable unit that measures DC magnetic fields with direct digital readout in mT or G. The unit is designed for wide range, auto-range, high accuracy, and ease of use. 

TD8620 includes three grade meters:

                                         Accuracy of TD8620-1 is ±1% of reading

                                         Accuracy of TD8620-2 is ±2% of reading

                                         Accuracy of Td8620-5 is ±5% of reading

2. Technical Specification

2.1 TD8620-1

2.2 TD8620-2

2.3 TD8620-5

3. Features

1) The TD8620 is used for measuring magnetic flux density, rang 0~2400mT.

2) Three accuracy classes are optional: class 1, class 2, and class 5.

3) Users can switch the units G or mT by on the key.

4) Auto-zero, auto-range and maximum maintain functions.

5) Backlight adjusted, battery display, and auto power-off.

6) Light-weight, low power consumption, and multiple Hall probes are available.

4. Introducture

4.1 TD 8620 front panel key are defined as follows      

                                                                                            Fig.01

1) ON/OFF: Turns power to the unit on/off.

2) Hold: Turn Max Hold feature on and off. Max Hold captures and displays the highest field reading.

3) Backlight: Turn backlight feature on and off. Backlight lighten up the LCD for reading.

4) NULL: Used to zero or null effects of ambient low level fields from the probe.When user pushes the NULL key ,"0000.0 G or 000.00 mT"displayed. The unit then automatically accepts whatever residual field it reads as a zero offset .

5) mT/G : Changes units from mT to gauss .Gauss is used in the cgs system :1 G=0.1 mT,mT is used in the SI system :1 mT =10 G.

4.2 LCD Display

                                                                                                        Fig.02

4.3 Back Cover

                                                                                   Fig.03

When the stud-snap battery is used up, you should take the follow steps to replace it. Firstly, use a long-stemmed driver to remove off the screw which on the hole shown in the Fig 03. Secondly, unfasten the snap of the battery, then take a new battery replace of the old ,fasten the snap , screw on. Finally replace the battery door.

4.4 Axial and Transverse Probes

TB8620 can use either axial or transverse probe shown in follows:

                                                                                     Fig.04

CAUTION :Care must be taken when handing the probe .The tip of the probe is very fragile. Pressure the Hall sensor can alter its calibration. Don’t apply more force than is required to hold probe in place. So there is no excessive pressure which will tend to bend or depress the sensor substrate and destroy the Hall element inside.

4.5 Connect the Hall Probe

                                                                               Fig.05

Plug the probe into the male connector at the top of the teslameter. Make sure that the groove of female connector with the probe and bump of the male connector be matched shown in Fig 05 . However, it is most important that certain precautions be taken when handing and installing probes so that they are not damage or destroyed ,and to preserve their accurate calibration.

4.6 Probe Operation

For best results , the instrument and probe should warm up for at least 10 minutes before operation. When magnetic field forward vertical cross the Hall sensor ,the polarity is positive(N)see Fig 06,or is negative (S).

                                                                                   Fig.06 positive(N) measurement

Probe readings are dependent on the angle of the sensor in relation to the magnetic field. The magnetic field should Vertical cross the sensor. Maximum output occurs when the flux vector is perpendicular to the plane of the sensor. The greater the deviation from Vertical orientation ,the larger error of reading.

                                                             Fig.07 Effect of Angle on Measurement

5. Application

 1. Permanent magnet magnetic measurement

 2. Mechanical parts remanence measurement 

 3. DC magnetic field source measurement

4. Magnetic separator working magnetic field measurement

5. Speaker magnetic field measurement

6. Permanent magnet separator working magnetic field measurement

7. DC motor working magnetic field measurement

8. Strong magnetic shielding magnetic leakage measurement

6. Packing