What type of contol system do I need?

[TurboME]

Please bear with me, I have little experience with control systems but I have some basic understanding how they work. I want to create, what I think should be a basic system, that regulates a pressure drop between two fluids.
The system will consist of an electro-proportional valve that controls flow of one of the fluids, and two pressure sensors, one for each fluid.
I need to figure out how I can set up a control system that will use the information from the sensors to control flow from the valve in order to maintain a constant pressure differential between the fluids. I can only control the flow of one fluid. As the pressure of the second fluid increases the valve needs to increase the flow of the second fluid to maintain the pressure drop. The way I see it, the controller needs to use the valve to maintain a constant voltage difference between the sensor inputs.
The system needs to cycle quickly and have a quick response as the pressure of the second fluid is constantly changing.
I just need an idea where to start. What type of control system would be best, PID, PLC etc..? Is there a simple controller on the market that could be programmed to do what I need? I apologize again for my inexperience.

 

[jraef]

Most good quality PID controllers should be able to do that simple task as a stand-alone system. I used the tried-and-true Honeywell UDC3000 for similar tasks many times. It is an older technology so I suppose there are even more powerfull controllers available now.

"Venditori de oleum-vipera non vigere excordis populi"

 

[RubenJ]

Why don´t you use a differential pressure transmitter with a simple PID controller, like C100 From ABB.
Differential pressure transmitter sends a signal to the controller proportional to Pressure drop between the 2 fluids and it´s more accurate than using 2 sensors.
This series of controllers can have a pulse output or an 4-20mA otuput so you can configure it as requirred by your valve.

 

[ICman]

There are several methods you could use. Since you want to control differential between the fluids, RubenJ's suggestion is good.

It sounds like what you need is a simple, single-loop controller. It can be incorporated in an existing control system (PLC, DCS, discrete controllers, etc.), or set up separately. You might use a local pneumatic controller or an electronic-based one (such as the Honeywell suggested by jraef).

You will also need to select a correctly-sized control valve with the appropriate actuation. I suggest you contact someone like Emerson Controls (Fisher-Rosemount), Foxboro, Honeywell, Omega, or preferably a local company that can provide all the components you need.

You should be able to find a local rep thru

http://www.isa.org.

Look for their directory.

Good luck!