Ucd3138 pdf

Ask a new question Ask a new question Cancel. Tags More Cancel. Share More Cancel. Similar topics. This thread has been locked. Genius points. That is why we recommend single ground plane in layout around UCD Up 0 Down Cancel. Yitzhak-san Thank you for answering. I have additional questions on UCD It was pointed out that there is a possibility of being reset by noise. Also, please tell me the guidelines. Please have it if there is material. Depending on how many layers your PCB consist of, the previous reference layout may work as well.

But this is not the only thing to follow. There are several helpfull tips in the document below that need to be carefully followed: www.

Think about driving your car with a dead time between the steering wheel and the tires. Every time you turn the steering wheel, the tires do not respond for, say, two seconds.

Causes for Dead Time Dead time can arise in a control loop for a number of reasons:. Sometimes dead time issues can be addressed through a simple design change. It might be possible to locate a sensor closer to the action, or perhaps switch to a faster responding device. Other times, the dead time is a permanent feature of the control loop and can only be addressed through detuning or implementation of a dead time compensator e.

Smith predictor. The heat exchanger is a realistic simulation where the measured process variable PV is the temperature of hot liquid exiting the exchanger. To regulate this PV, the controller output CO moves a valve to manipulate the flow rate of a cooling liquid into the exchanger.

The step test data below click for a larger view was generated by moving the process from one steady state to another. This is the same point we identified when we computed T p in the previous article. Locate the point in time when the CO was stepped from its original value to its new value. Applying the three step procedure to the step test plot above: 1.

As we had determined in the previous T p article, the PV starts a clear response to the CO step at Reading off the plot, the CO step occurred at Like a time constant, dead time has units of time and must always be positive. For the types of processes explored on this site streams comprised of gasses, liquids, powders, slurries and melts , dead time is most often expressed in minutes or seconds. The tuning correlations and design rules assume consistent units. Control is challenging enough without adding computational error to our problems.

As dead time becomes much greater than T p, a dead time compensator such as a Smith predictor offers benefit. A Smith predictor employs a dynamic process model such as an FOPDT model directly within the architecture of the controller.