DXGE-30T Zero Magnetic Shielding Magnetic Field Generation System

DXGE-30T Zero Magnetic Shielding Magnetic Field Generation System

introduction：

  We can individually develop and design a larger zero-field environment for you according to the needs of users, so that you can carry out your non-magnetic experimental projects in a sufficiently large zero-field environment. In addition to standard Pyrex alloys, We can also produce various types of amorphous soft magnetic materials and nanocrystalline soft magnetic materials. Samples can be added to the zero magnetic cavity for testing or coils can be added to produce a certain magnetic field to test the physical effects of the tested object.

  The zero-magnetic shielding magnetic field generation system solves the problem that Helm's three-dimensional geomagnetic compensation coil cannot shield the real-time fluctuations of the geomagnetism when the geomagnetic field is shielded, so that the magnetic field shielding effect can reach a higher level (less than 1nT). It is equipped with a high-precision fluxgate. In the case of high-precision linear power supply and three-dimensional equal-diameter Helmholtz coils, it can reach within the range of (0-100000nT) magnetic field. The three-component X, Y, and Z magnetic field generation can be accurate to 1nT, and the adjustment step is also It can be accurate to 1nT, making product production and experimentation in many fields such as scientific research, military industry, and medical treatment extremely meaningful, and has been widely used.

System composition：

The magnetic flux generating device consists of a group of three-dimensional coils and three corresponding power supplies. One group of three-dimensional coils is used to generate the uniform magnetic field required for the experiment. The three-dimensional coils are equipped with three power supplies to control the three-dimensional coils respectively.Each dimension has a set of coils, which are used to generate a uniform magnetic field. The high-precision imported fluxgate probe is placed in the center as the feedback test of magnetic field adjustment, and the feedback signal is adjusted by the upper computer to adjust the high-precision electric Source output current value, so as to achieve precise shielding of geomagnetism and generate the required magnetic field.The magnetic field measuring device includes CH-330F fluxgate meter and fluxgate probe, which is mainly used to measure the size of the magnetic field in the uniform magnetic field in the center of the coil and feedback the real-time magnetic field.

Magnetic field measuring device

  The upper computer software runs on the PC and consists of a control part and a collection part. It is mainly used to control the power supply current according to the collected real-time magnetic field value and the external signal sent by the control computer.The drive coil generates a magnetic field of a specified size. The experiment table is used to place the computer equipped with the upper computer control software; the fluxgate meter and 3 power sources are placed in the cabinet; the fluxgate probe is supported by the bracket and placed in the center of the coil in the uniform magnetic field area.The Helmholtz coil is a coil formed by connecting two coils with exactly the same radius and number of turns, arranging them coaxially and making the distance equal to the radius. It can generate extremely weak magnetic fields up to hundreds of Gs, which can be used to offset and compensate the earth's magnetic field, and to detect the characteristics of permanent magnets.The power supply is mainly used to supply power to the coil and drive the coil to generate a magnetic field.CH-330F high-precision fluxgate meter, VGA color 6-bit resolution; range 0- 1000000nT; division force 0.1nT; RS-232 and USB interface, BNC three-way analog signal output interface, with A set of fluxgate data communication and drawing software. The upper computer control software is composed of a control part and an acquisition part. The acquisition part is responsible for reading the current magnetic field measurement value by the CH-330F fluxgate meter and displaying it on the interface in the form of a curve; the control part is responsible for calculating the current value required to generate the specified magnetic field and outputting the current command to the corresponding power supply . The software adopts PID closed-loop control method to control the magnetic field in the uniform area of the coil center. The input terminal is the magnetic field value set by the user. According to this setting value, the software converts the corresponding control current value by the PID algorithm and outputs it to the power supply; the coil generates The magnetic field changes with the change of the control current. CH-330F fluxgate will send the changed feedback magnetic field value to the upper computer, and the software will continuously adjust according to the difference between the set value of the magnetic field and the actual value until The error is within the allowable range.

Performance index of magnetic field：

Principles of Software Control:

  The control of the geomagnetic shielding coil group is used to eliminate the influence of the geomagnetism; the control of the magnetic field generating coil group is used to generate a magnetic field of a specified size in the uniform area. The external input option box can choose whether to control the magnetic field setting by an external signal.When choosing to control the magnetic field setting by an external signal, its work flow:

①Receive the external control signal to control the geomagnetic shielding coil group, set the setting value of the three dimensions to 0nT, and start zero adjustment;

②The three-dimensional magnetic field value of the geomagnetic shielding coil group is adjusted to the specified range (±50nT), and the software sends a "ready" signal to the control computer and stops zero adjustment;

③After the control computer receives the "ready" signal, the user can start to set the magnetic field value of the specified dimension, for example, set Bx to 1000nT;

④After receiving the external control signal "Bx: 1000nT", the software controls the power supply corresponding to the X dimension of the magnetic field generating coil group, and uses PID closed-loop control to control Bx at about 1000nT. The specific adjustment accuracy can be adjusted in the software "Adjust Sensitivity"-item Set in;

⑤After completing the adjustment of the size of the magnetic field in the specified dimension, the software sends a "adjustment complete" signal to the control computer to remind the user to set the next magnetic field value.

  It is mainly used to adjust PID parameters so that the adjustment performance of the system is optimal among the indicators such as adjustment time, overshoot, oscillation, and steady-state error. Increasing Kp will reduce the steady-state error and improve the dynamic response speed of the system, but if it is too large, the number of oscillations will increase. Ki can be used to eliminate the steady-state error of the system. When Ki is appropriate, the characteristics of the system are ideal. However, the system with a large Ki has more oscillations; the integral control with a small Ki has less impact on the performance of the system, so the steady-state error of the system cannot be effectively eliminated. Kd control can reduce the overshoot of the system, overcome the oscillation, and shorten the adjustment time. When Kd is too small, the overshoot becomes larger and the adjustment time becomes longer. PID correction comprehensively applies the respective characteristics of lead and lag correction, using lead correction to increase the phase margin of the system and improve its dynamic performance; use the lag part to improve the static performance of the system, thereby improving the stability and rapidity of the system. PID calibration adopts the trial and error method, and the test principle is based on the principle of proportion first, integration second, and differentiation again, that is, the test is performed in the order of P, PI, PID, and satisfactory control parameters are obtained.

Brief introduction of main components:

 

Shielding tube

Provide a zero magnetic environment and reduce magnetic field disturbance.

The 3 layers of shielding layer can achieve the shielding effect of remanence ≤10nT, and the magnetic field fluctuation can reach ≤20pT,

The 5 layers of shielding layer can achieve the shielding effect of remanence ≤1nT, and the magnetic field fluctuation can reach ≤10pT,

The 6-layer shielding layer can achieve the shielding effect of remanence ≤ 1nT, and the magnetic field fluctuation can reach ≤ 1pT.

 

Torque-free coil

Magnetic field range: 0~±100000nT/+1000000nT (Magnetic field size can be customized)

Uniform magnetic field area: a quarter of the diameter of the coil, the diameter of the coil can be customized according to customer needs,Magnetic field uniformity: better than 0.5%; less magnetic leakage, large uniformity area; good uniformity.The coil winding is made of oxygen-free copper enameled wire; the coil frame is made of precision mold customized GFRP material;The connector is made of imported black FR4 epoxy board.

Circular three-dimensional equal diameter coil

Magnetic field strength range:-5000nT~ 5000nT;

Magnetic field uniformity area size: 100*100*100mm3; magnetic field uniformity: better than 1%;.

Magnetic field disturbance<1pT; with high-precision constant current source, the magnetic field step can reach 10pT;

The coil winding is made of oxygen-free copper enameled wire; the coil frame is made of precision mold customized GFRP material;

The connector is made of imported black FR4 epoxy board.

PC control software:

The control of the geomagnetic shielding coil group is used to eliminate the influence of geomagnetism;

The control of the magnetic field generating coil group is used to generate a specified size magnetic field in the uniform area.

The external input option box can choose whether to control the magnetic field setting by an external signal.

The size of the magnetic field generated by the coil can be fixed to prevent the test sample from causing the magnetic field generated by the coil

interference.

The change process of the magnetic field inside the coil can be recorded and saved in real time and exported to a table.