i do a research about process control in my lab. i have a problem when i have to find the model of the plant. there was 2 tank, the process tank (upper) and sump tank (lower). There was a pump which pumping the water from lower tank to the upper tank. Solenoid valve on the upper tank, throw out the water from upper tank to the lower tank.

now i try to find the model of level loop.
this loop contain of an upper tank, solenoid valve (outlet) and the inlet from the pump. and i have to control the level of water on the tank using solenoid valve (outlet valve).
are there anyone who understand about this??
r are there who have the references?

thank you
wildan

 

This is not a problem. You require a High Low level switch installed on the process tank. The 24 volts supply to the solenoid should be connected in such a way as to cut off supply to the pump when the process tank reaches high high level and to start the pump when it drops to a low level.

Regards.

 

Hello Wildan;

Have a look at the following site:
http://www.controlguru.com/

If you are interested in mathematical models and techniques for establishing the FOPDT models, you will find much worthwhile information there.

Hope this helps,
Daniel Chartier

 

Here is a Windows movie showing a vessel being automatically topped up using simple on off logic.

http://www.controldraw.co.uk/Movies/FillingLogic.wmv

Francis
www.controldraw.co.uk

 

Easy to read drawing on the main page.

Click on the middle picture at:
http://www.almegcontrols.com/

Thanks,
Bob Hogg

 

Hi,

I am a engineer in the company of Globeunion, and we are producing faucets and etc. I have been asked to design a new control system product (Danze, which is famous in United States) which will involve selecting a solenoid valve. I would like to know about the mathematical model of different companies solenoid valves. Could you please help me with this?

Best regards,
francis.peng
francis.peng @ globeunion. com

 

What speed of the process do you have? In a low frequency process (i.e. below 1HZ) you don't need a valve model. However if you are going to make valve semi analog output (with PWM signal), you will need only raise time and fall time.