ontrolling a hydraulic valve

[Lalith]

I am trying to simulate a pressure profile of a hydraulic cutter. The pressure is set according to the flow rate. There will be two sensors to measure the flow rate and the pressure. I am planning to use a PID control loop to control a valve for this. I believe using a look up table I could input my dynamic set point for the controller. I do not know whether I could implement this in LABview. Simply the set point of pressure will be a function of the flow rate. At the same time I want to log some other data like temperatures at different points. I am planning to use a NI PCI 6259 M series DAQ. I am wondering anybody has done similar nature of work. I was looking at “PID control multi channel .vi” example but did not understand how I could separate the channels, such that I could use two channels as inputs to the controller and rest to log data.

Any help will be highly appreciated. Thank you very much in advance.

[Tom.]

Hello,

For a better understanding of how to implement PID control with National Instruments hardware using the LabVIEW environment take a look at this DeveloperZone article Complete resources for a PID control system with NI M Series devices.

For using two channels with PID control I'd recommend looking at the Dual Channel PID.VI found in your LabVIEW example finder.

If you wanted the rest of the channels to log data you would have to add more channels to your DAQmx task and then index those out of the array that is returned and write those to a file, or simply set up a whole new task with the input channels you wish. For more help on this go to the LabVIEW example finder and navigate to Fundamentals >> File Input and Output.

Hope this helps

Tom | NIUK

[Lalith]

Hi Tom,

Here is my design. Could you please comment on my approach? I am new to LV and do not know whether I have made basic mistakes in my code. Thank you very much in advance.

Lalith