How to control a valve via a micro controller?

I have a reaction that produces a gas and i am trying to use a micro controller to control both the fluid in and the gas that comes out. This project is still in its infancy but if someone can provide me a manufacturer name or a device to look at for reference that would be great. However, what ever i use to controll the valve must be analog so that its not just a shut off valve.How to control a valve via a micro controller?
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http://www.metsoautomation.com/automatio鈥?/a>How to control a valve via a micro controller?
If it is a industrial project with economic support, the standard way is to go for a PLC (programmable logic controller). PLC's are microcomputers which are robust enough to work in a industrial environment and they can be interfaced easily to monitor or control any device found in the industry. You can find small PLC's and also huge PLC's, all it depends on whether you want to control a valve, as it is your case, or you want to control a whole oil refinery.Also they are scalable. In this case you need to know programming, control and basic electronics.


Popular PLC manufacturer: Allen- Bradley, Siemens.





If it is a individual project, PLC麓s could be expensive. You can go for standard micro controllers, almost any micro controller (there are hundreds different types) can control a single valve, they cost almost nothing (less than $10) .The problem is that you have to build all the interface and secondary circuit needed, which means that you have to know/learn electronics, programming, control, instrumentation, digital communication,...and so on.


Popular Micro controllers manufacturers are : Microchip, AVR

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