The hardware design of the viscometer system is mainly the design of some instrument circuits. The task is to drive the sensor to work at the resonant frequency and detect the amplitude of the sensor. Moreover, the closed-loop control is performed according to the primary and secondary approach control algorithm, and the current vibration frequency of the vibrating mechanism is displayed, so that the operating frequency and amplitude of the entire system remain constant.
The overall structure of the system is controlled by external keys to control the required vibration frequency and current signal output by the microcomputer, the drive circuit is used to make the vibration starting mechanism work at the resonant frequency, and the amplitude measurement circuit is used to obtain the tiny displacement of the vibration starting mechanism. Suzhou Taien Electromechanical Equipment learned that the A/D conversion circuit feeds back to the microcomputer, and the microcomputer adjusts the start-up driving signal through a certain control algorithm through comparison with the reference amplitude signal, and finally makes the instrument reach a balanced state.
Viscometer main components and functions
Viscometer is composed of stirrer, heater, temperature controller, bathtub, capillary viscosity fixture, mercury thermometer, lighting lamp, cooling fan and so on.
1. Stirrer: the working medium in the mixing tank. Make the temperature of each point in the bathtub uniform, speed up the temperature balance speed, and improve the control accuracy.
2. Heater: The instrument adopts a sealed tube heater. The heaters are divided into two groups, each group has two heaters, and the power is 600W. One of the heaters is a temperature control heater, and the other is an auxiliary heater for accelerated heating of the bathtub.
3. Temperature controller: The instrument uses Pt100 platinum resistance as the temperature sensing element, three-wire wiring system, adopts temperature proportional adjustment control mode, the resolution is 0.1 ℃, can automatically control the heater to heat and control the temperature of the bathtub working medium, and Displays the medium temperature.
4. Bathtub: The volume of the bathtub is Ф300x330mm, which stores the working medium specified in the test. There are four mounting holes for viscometer fixtures on the cylinder head, which can measure the viscosity of four samples at the same time.
5. Capillary viscometer fixture: it can reliably place the viscometer in the bathtub and adjust the verticality of the viscometer. When the constant temperature bath leaves the factory, there is no capillary viscometer attached. Users can order various models from the manufacturer according to their needs. viscometer and fixture.
6. Mercury thermometer: It can accurately measure the temperature value of the working medium in the bathtub. The thermometer used is different according to different test standards. Therefore, the constant temperature bath does not have a thermometer when it leaves the factory. Users can order it from the manufacturer according to their needs.
7. Lighting lamp: It is installed at the bottom of the bathtub with a new type of energy-saving light source without glare, so that the operator can clearly observe the scale value of the capillary viscometer.
