PID controller doubts

[Kakka]

Hi guys this question was asked to me when i attended for a interview ?

What will happen if a Derivative control alone is applied to a constant error system...

What will be the nature of output..?

Also i was asked a question regarding what will happen if we try to connect to devices using a cross connected ethernet cable...and also using a switch in between...?



what i know about the derivative control is that a derivative controller will help to suddenly bring the error back under control...but there is a possibility of disturbances iccuring in between....

 

[Peter Nachtwey]

Hi guys this question was asked to me when i attended for a interview ?

What will happen if a Derivative control alone is applied to a constant error system...

What will be the nature of output..?

The derivative of the error is 0 so the output due to the derivative alone is 0.

Also i was asked a question regarding what will happen if we try to connect to devices using a cross connected ethernet cable...and also using a switch in between...?

This is not a good question. Some switches will automatically switch the cable around so they work but older hubs may not automatically switch the send an receive lines around.

what i know about the derivative control is that a derivative controller will help to suddenly bring the error back under control...but there is a possibility of disturbances iccuring in between....

The derivative gain adds damping and resists change in the error either bigger or smaller but it will not try to correct the error.

 

[Kakka]

re

thank you peter. thank you for reply...