PID Tuning: Split Range ControlLearn MPS Technology on mps-technology.net. PID Tuning: Split Range Control article will help answer your questions on MPS Technology.We at mps-technology.net specialize in MPS Technology. MPS Technology at mps-technology.net provides the most up to date news and articles. If you have questions please do not hesitate to contact us.
A very common control scheme is split range control in which the output of a controller is split to two or more control valves. Controller output 50% - Valve A is fully open and Valve B closed. Controller output 75% - Valve A is fully open and Valve B 50% open. The solution is to replace the split range controller with two independent controllers, as shown here, both reading the same pressure transmitter, but one controlling the flare valve and the other the suction valve. Article: A very run-of-mine control scheme is split range control in which the output of a controller is split to two or more control valves. For example:
Controller output 0% - Valve A is fully open and Valve B fully closed. Different arrangements are possible. For example, this figure shows a split range pressure controller on a separator with two valves, one to the flare and one to the compressor suction. In this case, the 'split' is configured as follows:
Controller output 0% - Both valves are closed. The idea is that the suction valve is used for normal pressure control while the flare valve only opens to disperse high pressures. In the pertinaciousness described above, the flare valve will need to open quickly in response to high pressures, but the compressor suction valve will need to move much more slowly to prevent instability in the compressors. The main problem with split range control is that the controller only has one set of tuning parameters. If the controller is tuned to be fast mimicking to optimise the performance of the flare valve, the suction valve will also move rapidly to produce unstable gas flows to the compressors. If the controller is tuned slower to stabilise the compressors, then the flare valve will not open fast enough as the pressure rises. A further issue is that the process response of the route to flare generally differs to the process response of the route to the compressors, so both routes will same require very different tuning for optimal control. The solution is to replace the split range controller with two independent controllers, as shown here, both reading the same pressure transmitter, but one controlling the flare valve and the other the suction valve. Not only can each controller be tuned correctly for its dedicated service, but different setpoints can also be used to prevent the flare valve from 'popping' unnecessarily.
The ease with which a split range controller can be replaced with two ordinary controllers depends on a number of factors. If the 'split' is shaped in the DCS or PLC so that each valve has its own output from the control system, then the too of a new controller is simply a matter of software configuration. However, occasionally, the control system only has one output wired to both controllers and the 'split' produced by configuration of the valve positioner. A new output will then be required from the control system to one of the valves and the valve positioners must be reconfigured to operate over the full 0-100% output range.
|
Advice Home Business Technology Online Advertising Motivational Internet Marketing SEO Help Online Games Science Articles Happiness More Articles:1. UPS Batteries Could Be a 'Lifesaver'! Summary:The UPS Battery could be a lifesaver for some companies, just by giving people time to safely shut down their computer. We all have done that at one time or another but with the USP battery you would have still had enough time to save all that hard work that you did all day plus do a soft shut down. Article:The UPS offensive linesman could be a lifesaver for some companies, just by giving people time to safely shut down their computer. These batteries are something like a surge protector… 2. Motion Detector Technology Summary: There are many common uses for motion detectors that most people find convenient and helpful in very common, everyday situations, and there will be some new and innovative uses that we may see more and more of in the future.Residential UsesResidential consumers are putting the motion detector to a variety of uses. Motion detectors have evolved a great deal over the last few years to incorporate more features that are useful to more people, and the development and expansion of motion det… Instant Approval Credit Card Seiko Watches DIRECT LINE Car Insurance Kwik Fit Car Insurance Jet Airways 3. Fire Evacuation Drill with a Difference Summary: The stakes are high.The fire protection alarm system in our building is wired in such a way that any triggering of the alarm by activating a break glass, smoke detector, heat detector or sprinkler flow switch will eventually trigger the general alarm for the whole building if it is not acknowledged and reset back within 3 minutes. In addition, the original wires would need to be disturbed and re-looped - something engineering people would not be keen to do - as it might give rise to oth… 4. Encompix ERP Software for Engineer-to-Order Manufacturers Releases New Version Summary: They are Customer Relationship Management (CRM) to integrate prospect visibility and tracking through customer orders and service, a new Nonconforming Materials (NCM) module to integrate quality tracking through purchasing, shop floor and inventory and a new Engineering Bill of Materials (E-BOM) to provide item revision control, a BOM import and BOM posting to jobs. Article:The latest edition of Encompix ERP Software, version 9.30, was released on December 1, 2005. According to hear Me… |
||||
