Pressure Vessel Pro vs PIDTune

Pressure Vessel Pro - Pressure vessel calculations for iOS. The easiest way to do basic pressure vessel stress calculations. Simply select from the available geometries, enter in the required dimensions and the answers will be generated complete with the formulae. You can also easily print or email a PDF of your results along with a schematic of the pressure vessel. Pressure Vessel Pro Features: - Universal - designed for use on all sizes of iPhone, iPod Touch, and iPad - Share or print a PDF report of the results - Extremely flexible unit system. Choose Metric, English or mix and match units. - Save multiple cases for later reference - Tap a cell to show detail and formulae The properties calculated include are: • Longitudinal Stress • Hoop Stress • Shear Stress • Volume • ASME Boiler & Pressure Vessel Code Design Thickness • ASME Boiler & Pressure Vessel Code Design Pressure Pressure Vessel Pro includes the Following Integrated Calculations: • Vertical tanks • Horizontal tanks • Spherical tanks Pressure Vessel Pro includes the Following Component Stress Calculations: • Cylinders • Hemispherical Heads and Tanks • Elliptical Heads • Torispherical Heads Pressure Vessel Pro includes the Following ASME Boiler and Pressure Vessel Code Section VIII, Division I Design Calculations: • Cylinder Thickness • Cylinder Pressure • Hemispherical Heads and Tanks Thickness • Hemispherical Heads and Tanks Pressure • 2:1 Elliptical Head Thickness • 2:1 Elliptical Head Pressure • ASME (dished) Heads Thickness • ASME (dished) Heads Pressure Check out our other engineering apps by searching the iTunes store for: • Moments of Inertia • Mohr's Circle • Stress Concentrations Pro • Stress Intensity Factors Pro or search J.R.Hobbs to see them all.

PID Tuner uses the IMC (Internal Model Control) method to calculate PID tuning parameters. I’ve tried a lot of tuning methods over the years and have found this one to be the best. The app is written for the iPad to show all the information on one page. The program calculates: PID Parameters: Controller Gain (Kc) Integral Time (Ti) Derivative Time (Td) For process types First Order with Dead Time (FO) Second Order with Dead Time (SO) Integrating or Long Time Constant with Dead Time (I) For controller types Parallel (non-interacting) c(s) = Kc (1 + 1/(Ti s) + Td s) Series (interacting) c(s) = Kc (Ti s + 1)/(Ti s)(Td s + 1) For controller modes PID PI You can either enter the process gain (Kp) directly or enter the changes in the controlled virable (CV) and manipulated variable (MV). Tuning aggression is adjusted using the slider to set the closed loop time constant to the process time constant ratio (λ/Ƭ). The closed loop time constant (λ) is the time the controller is expected to reach set point (plus the dead time (ϴ)). Setting the closed loop time constant to process time constant ratio (λ/Ƭ) to 1.0 will make the MV change to its final value and allow the process to settle out to the setpoint. Setting (λ/Ƭ) greater than 1.0 will give a slower responce. Setting (λ/Ƭ) less than 1.0 will cause the MV to make a larger change and then reduce to its final value. Tight tuning would be to set the close loop time constant to the dead time. Use the Integrating Process type (Ƭ = ∞) for both integrating processes or processes with long time constants. These processes use the maximum slope as the process gain. Tuning aggression for these processes is determined by setting the closed loop time constant to the dead time ratio (λ/ϴ). Once again, setting the closed loop time constat to the dead time gives tight control. References: “Probably the test simple PID tuning rules in the World,” Sigurd Skogestad, Jounal of Process Control, July 3, 2001 “Consider the generalized IMC-PID method for PID controller tuning of time-delay processes,” Y. Lee, S. Park, M. Lee, Hydrocarbon Processing, January 2006