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Engineering using Spreadsheets

Ziegler Nichols closed loop tuning calculator

Description
How it works








This tool will calculate the tuning parameters for a first order process with delay using the closed loop Ziegler Nichols tuning rules.

Download

.xls file (23 KB)

Background

The closed loop Ziegler Nichols tuning method is widely taught in academics, but has limited practical application due to risks of driving a process into continuous cycles. This tool makes it easy to calculate the closed loop tuning parameters by using the open loop process parameters (which are safer to obtain), and without the requiring a closed loop test on the process.

How to use

Key in the first order process parameters (Gain, lag and delay) into the spreadsheet, the tuning parameters for P only, PI and PID controllers are obtained. Note that this tool requires a minimum amount of delay. A delay free system will not go into cycles with only a proportional controller, and hence this method will not work. If the tuning parameters are not found, the cells show "#VALUE!" error. Also, the process gain must be scaled (dimensionless).

Lets take an example, we will choose the same process that we used for the Z-N tuning calculations using the Bode plot, that is

Process Gain = 2,

Lag = 3 s, and

Delay = 2 s

The following tuning parameters are obtained:


Results