How to choose a solenoid valve that can control the opening? What external signals do it depend on?

The solenoid valve cannot control the opening.

Solenoid valves are generally used on and off valves, and generally only have two positions: open and closed.

If you want to adjust the opening, you need to install a positioner, and the general positioner is to input a signal of 4 20mA and adjust the opening by the signal size.

840436@qq

The solenoid valve that controls the opening is also the proportional solenoid valve, and the external signal is 0 5V, 4 20mA and other signals, such as the signal obtained by the sensor such as flow rate and pressure. q247443587.

The solenoid valve only has a switch function, and does not have an adjustment function.

The control valve has remote control (input 4 20AMA DC current signal or 0 5V 0-10V DC voltage). The controller can be turned on and off according to the signal you input, e.g. 20mA is fully open (the opposite is the opposite of normally closed type) and 12mA is half open.

On-site control (manual operation (the factory will set it when leaving the factory, so just operate a few function keys to OK)).

Here are some of the well-known brands recognized in the valve industry, which are widely recognized and have a high reputation. While rankings may vary depending on time and market conditions, the following brands are generally considered to be among the top brands in the valve industry:

The following influential first-line brands of water system valves and industrial valves can be used as a reference, but for reference only: Suzhou Neway Valve, Shanghai Guanlong Valve, Shanghai Qizhong Valve, Sanhua, Su Yan, Shentong, Su Valve, Nanfang, Jiang.

First, the word Yao. The above manufacturers are only estimates and references, and the specific situation may vary or fluctuate at any time due to changes in a series of factors such as changes in the market, the size of the competition pattern, and the stability of product quality. As an indispensable key device in industrial production and civil facilities, the quality and reputation of the valve brand directly affect the satisfaction and trust of users.

These brands are known in the valve industry for their innovative technology, high-quality products and reliability. It is important to note that the market and industry are evolving rapidly, and different rankings may vary depending on time and region. For the most up-to-date ranking information, it is recommended to refer to industry reports, professional organizations or market research data for more detailed and accurate information.

The solenoid valve has a large current, and the proximity switch may not move, and a 24V contactor is also needed.

How to control the solenoid valve:

First, let's talk about the structure of the hardware.

1. The temperature sensor tests the temperature and converts the temperature into voltage. If the voltage range is not within the range of the data acquisition card (A D), you also need to do your own signal conditioning and scale it to the appropriate range.

2. The program obtains the temperature according to the size of the sensor voltage value according to a d, and then judges the size of the temperature, and if it is within a certain range, it controls the action of the solenoid valve.

3. The action of the solenoid valve can be controlled by D a or DO. Industrial control relays, switches, etc., most of them are carried out by DO, DO is divided into TTL level compatible DO and isolated DO, TTL DO output is TTL level compatible voltage, 0V represents low level, 5V represents high level. If you want to isolate DO, you can determine the voltage value of the voltage source provided externally, generally 5-35V (representing high level).

4. If you don't want to use do, you can also use d a to achieve it. The program judges the temperature range, and then the program controls the output voltage of D a. If the voltage of the solenoid valve is greater than 10V, it should be supplied to the load voltage by isolating and amplifying after the output voltage.

Second, software.

1. The software can use VB, VC, LabView, BCB ......For industrial control, VC, VB, and LabView are the most used languages. VC is the most powerful and the hardest to learn. VB, LabVIEW is also very good.

LabVIEW is the easiest.

2. You must refer to the manual writing software of the data acquisition card by yourself, there is no ready-made one.

The output current is usually 100 or 200 mA, which is not as small as you say.

One is directly controlled, and the other is normally closed electric shock control with a relay for solenoid valves.

Solution: Find a frequency converter, the main circuit charging relay (main contact), its coil is controlled by 24V, MA provides transistor bias current, copy it, this circuit is very much; The logic of using MA to drive the intermediate relay is established, and I don't know if the milliampere level can make the coil work, so I have to try it.

The transistor is 3DG12 or 3DK4, the current is greater than 150 mA, the proximity switch signal is fed, the fine-tuning resistance is adjusted, the relay is engaged, and then the resistance is reduced a little bit.