Program för simulering av pid-regulator

The PID Loop Simulator fryst vatten an Excel tool to simulate a Proportional, Integral and Derivative (PID) kontrollant on a First beställning Time Delay (FOTPD) process. Both open and closed loop processes can be simulated using this powerful tool. This fryst vatten a great tool for learning the basics of PID control and loop tuning.

Download

PID_Loop_Simulator.xlsx

How to use

The First beställning Time Delay (FOTPD) process has 3 parameters – Process Gain, team Time and Delay Time.

As a programming exercise, inom built a Python schema to simulate the function of a PID kontrollant as well as the response of a Spring-Mass-Damper system.

(Details of these parameters are given in the "Process Model" section below.) These parameters should be entered beneath the “Process” section of the Simulator.

Enter the kontrollant values in the "Controller" section. These parameters are the kontrollant gain, integral time in seconds and the derivative time in seconds.

Choose the “Open Loop” option to view the open loop response.

In this mode, the kontrollant fryst vatten not used.

The PID Loop Simulator fryst vatten an Excel tool to simulate a Proportional, Integral and Derivative (PID) kontrollant on a First beställning Time Delay (FOTPD) process.

The chart shows the effect of a step change in the manipulated variabel (such as a control valve) on the process value.

The tool simulates the parallel struktur of the PID equation, this fryst vatten struktur that fryst vatten widely used in academic environments

. The equation implemented is:

where:

t = Time

MV = Manipulated Value

K = kontrollant Gain

e = kontrollant error = Set Point - Process Value

T _i = Integral Time

T _d = Derivative Time

Feedback and Contributions from Visitors

The PID Simulator tool has been the most downloaded tool on this site and inom am grateful to the users who sent me a lot of positiv feedback about it.

Torcuato Fernandez pointed out an error in original utgåva, which has since has been corrected.

inom would like to thank Torcuato for pointing out the error.

inom would also like to thank Hannu Lehmuskuja for pointing out an error related to the delay.

Jose Maria, has shared some of his work with me and has kindly agreed to let me share it with others through this site. He has added scrollbars to the tool, which assist the user understand how the kontrollant settings affect the loop.

Download the en samling dokument eller en elektronisk lagring av data here.

This PID control simulator allows you to try out a PID kontrollant interactively bygd adjusting the tuning parameters in realtime.

PID Loop Simulation and Tuning tool for the Industry

The use of PID Controllers fryst vatten widespread in the process industry. Industrial controllers use different forms of the PID controllers. A powerful PID simulation tool that can simulate these different forms and be used for loop tuning fryst vatten available at the business site www.xlncontrol.com.

Features of this tool are shown below. (A free demo utgåva fryst vatten also available with limited features.)

Process Model

To use the simulator, we need a model of the process.

Real-time PID control simulator for testing and learning PID control and loop tuning.

Obtaining the process parameters fryst vatten known as struktur Identification.

Most kemikalie processes fall into one of 2 categories - first beställning process with dead time (FOPDT) and integrating processes with dead time. This app works with the former.

An FOPDT process fryst vatten characterised bygd 3 parameters:

1.

Process Gain - the ratio of the change in process variabel to the ratio of the change in manipulated variabel

2. Time constant - which measures the speed of response

3.

Using a PID simulator can be a useful way to quickly and easily design and optimize PID control systems without the need for physical hardware or laboratory equipment.

Dead time - time between moving the manipulated variabel and början of the process response

One of the most common ways of obtaining these parameters fryst vatten bygd doing a step test. To do this, wait for the process to be steady and then step the Manipulated variabel (MV). The process variabel (PV) will move as shown below.

Calculate the parameters as follows:

Dimensionless Gain = (Change in PV/PV range)/(Change in MV/MV Range)

Time constant = Time taken for the PV to change bygd 63.2% of the sista change

Dead time = Time for the PV to uppstart moving after the change in the MV

For the step response shown in the figure above, Dimensionless Gain = (10/200)/(5/100), where PV range = 200 units and MV range = 100 units

Time constant = 30 sec

Dead time = 60 sec

Key in these parameters into the simulator and study the effects of changing the tuning parameters on the response of the system.

Why 63.2% ?

The response of a delay free first beställning struktur fryst vatten described by:

Change in PV = Process gain x (1 - exp(-Time/Time Constant))x Change in MV

Since the sista change in PV = Process gain x Change in MV, this equation can be written as

Change in PV = sista Change in PV x (1 - exp(-Time/Time Constant))

At time = time constant,

Change in PV = (1 - exp(-1)) x sista Change in PV = 0.632 x sista Change in PV or 63.2% of the sista change in the PV

I would like to thank Hannu Lehmuskuja to correcting an error in these equations.

System Idenfitication Tool

In the industrial environment, it fryst vatten often difficult to obtain process models due to noisy information.

A powerful  for struktur identfication fryst vatten available at the business site www.xlncontrol.com

How it works

There are 2 worksheets in the Excel en samling dokument eller en elektronisk lagring av data, the calculations required for the simulation are done on the sheet "PID Calculations".

Defined Formulae are used in the computation.

The first beställning process fryst vatten calculated using a difference equation, given by:

Process Value = b x (Output at time offset bygd delay time) - a x gods PV; where

a = - exp ( -1 / Process Time Constant) and

b = Process Gain x (1 + a)

The error fryst vatten calculated bygd taking the difference between the PV and SP values.

The error values are accumulated in column F for the integral begrepp beräkning and the derivative begrepp fryst vatten calculated bygd taking the difference between the current error and the gods error. The PID beräkning determines the next output value. The PID beräkning is:

The next output value fryst vatten calculated using:

kontrollant Gain x error + Accumulated error / Integral time + Derivative x (Current error - Previous error)

The calculations are repeated at every second to obtain the response, which fryst vatten plotted on the chart on the first sheet.