GNT Series Computer Controlled Electron Universal Testing Machine

1.tensile, compression and bending test of metal and non-metallic. 2.Test of Poisson ratio u and sheet metal n and r. 3.DSP

Main Technical Parameters

GNT Series Computer Controlled Electron Universal Testing Machine

      The device is applicable to tensile, compression and bending test of metal and non-metallic materials. Together with the non-contact extensometer, the device can conduct non-contact deformation measurement to ultra-fine, ultra-thin and brittle specimen as well as the measurement of axial and transverse deformation, especially for the measurement of Poisson ratio μ and sheet metal n and r. Equipped with the DSP platform-based measurement and control system independently developed by the company, the device can achieve the three-closed-loop control of stress, strain and displacement, and have the function of switching between a variety of control methods.

Applicable specimens: rods and bars, plates, deformed steel bars, fasteners, etc.

Function Introduction

[The device’s structural features are as follows]

1.A transmission control system

The transmission control system adopts delta all-digital advanced AC servo driver for general purpose and high-precision, high response frequency Delta AC motor, and achieve all-digital closed-loop control through PID control method. The motor which is connected to Germany Alpha reducer drives the high-precision grinding screw to rotate with the help of synchronous cog belt. The transmission structure combining the reducer and the grinding screw ensures the high efficiency, low noise, smooth transmission, and high precision of beam movement.

2.Rack

The frame structure is made up of four stand columns fixed on the beam and a table top. The reducer mobilizes two gapless precision ball screws, driving the beam to move up and down. The rack which passes the load has reasonable structure, good rigidity and stability, smooth loading feature and long service life. The limit device will initiate test protection during the test.

The overload capability of the mainframe can be up to 200%, which ensures the long-term stability of operation of the Tester.

3. Force Measurement System

The American strain gauge load cell with high stability, high accuracy and high sensitivity is employed. The system is equipped with measurement controller with high accuracy, low drift, and high resolution. The sampling frequency is high. The force resolution is 1/500, 000 with a load measuring range of 0.2% -100% of the full capacity. There is no difference between the internal and external and the whole resolution remains unchanged.

4.Deformation Measuring System

Deformation measurement is achieved through the equipped deformation sensor (electronic extensometers) and NCS measuring and control system. There are various electronic extensometers in terms of the specification of gauge length and strain, meeting the requirements of measuring materials of different shapes and achieving high measurement accuracy and high stability.

5. Fixture

There are different types of fixtures, manual, pneumatic or hydraulic, suitable for different types of specimens. The subsidiary fixture is varied as the test method varies.

 DSP All-Digital Closed-Loop Measurement and Control System

Reputation First, Service-Oriented

[Description of the Measurement and Control System]

The high-precision measurement and control system, adopted by the electronic universal Tester, is independently developed by NCS which owns independent intellectual property rights of the system. The system is an all-digital closed-loop control system which integrates high-precision data acquisition & processing and process control. The Tester’s measurement and control system is based on the American Texas Instruments’ DSP chip. And USB2.0 is applied for fast communication with PCs. CPLD is adopted to achieve control of the high-precision acquisition part. The master control DSP is released for better control. The adopted popular PID control method realizes the all-digital closed-loop control of force, displacement and deformation.

[System Features]

1.DSP’s Control Core

The U.S. Texas Instruments' DSP functions as the control core and the control chip is focused on the field of motion control. We have chosen the 32-bit DSP controller which is currently one of the most advanced processors. The DSP controller has a frequency of up to 150MHz, greatly improving the control precision of the control system and the processing capability of the chip. The DSP controller is based on the C/C ++ efficient 32-bit DSP core and provides floating-point math function library, realizing the floating-point calculation in the fixed-point processor in a convenient way. The chip integrates a 128K flash memory which can be used for development and the simple re-programming when upgrading the on-site software. The chip’s standard communication ports can provide simple communication ports for hosts, test equipment, monitors and other components.

2.Data Acquisition System of High Acquisition Frequency and High Precision

The acquisition system adopts high-precision 24-bit AD converter and is still able to guarantee a 20-bit acquisition precision at an acquisition speed of 1 kHz. The acquisition system avoids lots of amending to acquisition data to acquire high resolution, which otherwise affects the accuracy and timeliness of the data. The system guarantees the synchronization of the signal acquisition by using specialized methods. The use of floating-point math function library provided by the chip realizes floating-point calculation in the fixed-point DSP, further improving the accuracy of the acquisition system and ensuring a resolution of 1/500,000.

3.High-Pass Band Width

The band width reflects the Tester’s real-time response to displacement, stress and strain and is the key indicators to measure the measurement and control system of the Tester. As the measurement and control system does not amend the data acquired, the pass band width of the measurement and control system is comparatively superior to 100Hz under an acquisition frequency of up to 1 kHz.

4.Adoption of the Mature PID Algorithm

The closed-loop control of displacement, stress and strain is achieved, ensuring the automatic and smooth switch between the control loops.

5.USB Communication

The interface used for the communication with the host is the mainstream USB 2.0, which will be the mainstream of future communication development. The USB 2.0 interface has a communication rate of up to 480 Mb/s and is flexible in terms of communication patterns, i.e. control, interrupt, bulk and real-time. With USB2.0 communication technology adopted, the capability of transmitting data between the PC and the Tester is greatly enhanced, the man-machine interface of the PC is improved and the overall performance of the Tester’s control system is promoted.

6.Control Circuit

The control system uses ultra-large-scale programmable logic control integrated circuit. As all AD acquisition control and input & output are achieved through the integrated circuit, the monitoring and control circuit board thereby has the characteristics of compact in layout, less discrete devices, low power consumption and less heat, greatly improving the working stability of the system; secondly, the programmable logic controller can also add corresponding functions as needed without having to add hardware circuit, thus greatly improving the system’s scalability and facilitating the realization of the measurement and control system’s diversification according to customer requirements.

7.Measurement and Control System

The system adopts the 4-layer PCB board, improving the anti-jamming capability of the circuit board, effectively inhibiting the circuit board’s electromagnetic radiation, making the electromagnetic compatibility (EMC) of the circuit board better and enhancing the working stability and reliability of the system. (EMC: Electro Magnetic Compatibility refers to equipment or a system’s capability of not producing unbearable electromagnetic interference to any equipment in the electromagnetic environment when running in the environment in accordance with requirements. Therefore, EMC implies two aspects of requirements: on one hand, the equipment's electromagnetic interference to the environment in normal operation can not exceed certain limits; on the other hand, the equipment has a certain degree of immunity to electromagnetic interference in the environment, i.e., electromagnetic susceptibility)

8.Redundant Design for System Protection

The Tester may be broken during the experiment due to some unexpected factors such as the negligence of the operator, which sometimes may endanger the safety of the laboratory technician. Therefore, the Tester must be equipped with a limit device and protective measures like overload protection. The system adopts the redundant design for the protective system, greatly improving the security level of the Tester.

9. Reserved Standard Interfaces

Because the system has adopted an ultra-large-scale programmable logic IC, unused function interfaces can be set. Standard interfaces such as digital IO, AD conversion and serial port are reserved for the measurement and control system to facilitate future upgrading.

Introduction of Professional Test V2.0 Test Software

[Description of the Tester Application Software]

The application software is used to set the test method, control the experiment process and save the test data & graphics at the end of the test. Based on a deep understanding of relevant standards, especially the newly issued GB/T228.1-2010 standards, the programmers of the application software have made a lot of changes to the application software to fully meet the requirements of the new standards. This application software has the following characteristics:

Easy to use: for most tests, only a few common parameters need to be set and there is no complicated test setting.High adaptability: many parameters can be customized by users and they can select different test methods according to their actual specimen requirements.Modular design: the software is divided into several modules, making it convenient for upgrade and facilitating sub-rights management. Main modules: the test-parameter-setting module, the test-process-control module, the test-report-management module, the graphical analysis module, the database module and the auxiliary-function module.The data processing algorithm is more optimized and more accurate, fully complying with GB/T228.1-2010 standards.The application software is more user-friendly. Users can program according to their needs and customize their test reports with respect to the style of the test report.Unit  conversion: users may select the appropriate unit (load: N, kN, kgf and lb; deformation: mm and inch) as needed before each test.Automatic intelligence, there is no need to make level choice or preset the maximum stress or maximum coordinates. The coordinate system automatically changes and the user will always see full curves.The online help documentation: on-line help information which should be as detailed as possible is provided before and after the test. Fine adjustment to the result is allowable: the user can make fine adjustments to the test result by customizing the key parameters or manual operation, for example, data such as the corresponding elastic modulus and Rp0.2 can be re-calculated by customizing the starting and ending points of the elastic segment.

Diversified use of queried data: users can query the previous test data through a combination of multi conditions, greatly facilitating historical data query, curve comparison and data comparison.

Linearity correction to the sensor, extensometer, etc. is made segmentally, avoiding the linearity error of the sensor, extensometer, etc.

The maximum load limit, users can set the maximum load of the Tester themselves, and the Tester will automatically start to unload to protect itself when the load reaches the protection level.

Main Technical Parameters

Model No. Specification

GNT 1

GNT 2

GNT 5

GNT 10

GNT 20

GNT 50

GNT 100

GNT 200

GNT 300

GNT 600

Test force

Maximum test force (kN)

1

2

10

20

50

100

200

300

600

Measuring range

0.2 % - 100 % FS (full range without step division)

Error of indicating value

± 0.5 % in measuring range

Resolution

1/500000

Acquisition rate

≤ 1000/s, adjustable

Band width (Hz)

> 100Hz

Displacement

Stroke range (mm)

700

800

600

600

600

Resolution (μm)

0.015

Range of traveling speed

0.001 – 500 mm/min (Stepless adjustable)

Error of traveling speed

± 0.005 mm within 1 mm/min Other speeds: within ± 0.5 % of setting value

Deformation

Measuring range

0.2 % - 100 % FS (full range without step division)

Resolution

1/500000

Acquisition rate

≤ 1000/s, adjustable

Class

Class 0.5

Control

Control mode

Displacement, strain, stress, holding, switch freely and transit smoothly.

Coaxality

Loading coaxality

> 8 %(in line with ASTM)

Communication

USB 2.0

Max. speed: 480 Mb/s

Round sample fixture

Diameter Φ (mm)

Customizing as required

4 - 9

4 - 16

8 – 16; 16 – 26; 26 – 36

Plate sample fixture

Thickness (mm)

A set of waving fixture (can be customized as required)

0 - 7

0 - 14

0 – 10; 10 – 20; 20 – 30

Power supply

220 V ± 10 %, 50 Hz

380 V ± 10 %, 50 Hz

Motor power

kW

0.75

1.5

2.5

2.5

3.5

Host dimensions

(H×W× D) mm

1730×650×330

1900×760×460

2100×1050×750

2500×1160×715

2850× 1330× 860

Total weight

kg

About 150

About 350

About 1200

About 1500

About 2000

Safety

Protection function

Higher and lower limit, overspeed and overload protection, redundant design of protection function

Software

Operating environment

Windows XP/vista/Win 7

GNT Series Computer Controlled Electron Universal Testing Machine