#Plc that run from scilab install#
#Plc that run from scilab zip file#

The formula for calculating the closed loop poles is aggressive but since the model is fits the actual data very well the tc can be more aggressive. It is the derivation of the IMC SOPDT gains. Actually IMC attempts to place one real pole at -1/tc and cancel out the other two poles with zeros so the response looks like there is just one pole. I used the Internal Model Control, IMC, method that the controlguru uses. This will require scaling or unit analysis to covert my calculated gains to PLC conts out/counts in gains. Some controllers have controllers where the gain is counts of output per counts of error. The calculated controller gain has units of percent control output per unit of error which is degrees fahrenheit in this case. If your input file uses minutes then no adjustments are necessary. Because the time base in the hotrod.txt is in seconds, the time constants need to be converted to minutes. First, most PLCs use time constants in minutes. The PID parameters may not be directly useable for all PLCs or closed loop controller. The PID gains are calculated assuming the ISA model of dependent gains. Make the closed loop time constant smaller for a stronger response and longer for a weaker response to errors. The final output shows the plant open loop gain, two time constants, an offset ( ambient temperature in this case ) and a dead time.Ī closed loop time constant needs to be calculated to determine how strongly the PID parameters will react to errors. The estimated response and actual response ( PV ) should be close to identical.

There is also a plot that shows how well the model can estimate the actual response using the same input. The output is a some mathematical data about how good the fit is.

This file was originally generated by Ron Beaufort from his 'hotrod' tuning class. I have included a file called hotrod.txt. The script will take about a minute to run. You need to edit the path to the data and make sure that the delimiter is set right. Time, control output in percent and the process variable. The input file must be a text type file like a comma, tab or space separated variable file that has 3 columns.

#Plc that run from scilab install#

You must install python3, numpy, scipy and matplotlib or Anaconda to run the script.

#Plc that run from scilab zip file#

Attached is a zip file that contains a python script that calculates the PID gains for SOPDT systems.