How can i configure my PID Vi to work in the range of 0-100%

[Wormwood]

I've a VI that controls the level of water in a tank. And i've used a PID VI to work as a controller for the water output at the bottom of my tank, however, the controller opens and drain the water in the -100% range. My intention is that the controller should be able to fully shut at 0% and fully open at 100% and not from -100% to 100%. What am i suppose to do?

The attached is the VI i've written

With Regards

Wormwood

Message Edited by Wormwood on 12-20-2007 12:15 PM

[ShotSimon]

Can you just highlight on the front panel using the text tool (using the tools pallet) and change "-100%" to "0%"?  I need to update my Labview at home...sry but I can't open your *.vi till morning.

[Wormwood]

Using just texttools would only make a difference in the appearance, however, in the calculation it would still work with the values between -100% to 100%, (I think so?:)

With Regards

Wormwood

Message Edited by Wormwood on 12-20-2007 12:43 PM

[ShotSimon]

Can you just change your input cluster to the PID controller (output range low) to 0?  I tried this and it seemed to work.  SS

[Wormwood]

Using -100% to 100% as the default values given by the output cluster, my system at -100% is at fully open position and 100% at fully shut position . Changing the output cluster lower range -100% to 0 would cause my controller to stop operating in opening position range as now the range is 0 - 100, which is the shut position. This would cause my level never to drop since it could no longer open to drain the water.

(*The characteristics of a normal controller output is to be able to work in the range of 0-100%, fine tunning itself to bring the process value to the setpoint.)  

With Regards

Wormwood

[ShotSimon]

Sorry I thought the problem was more basic.  There are plenty of PID control examples:  Tank Level.vi

This looks almost identical to what you are describing.