Chapter 4  Error and warning messages

1. ``Error Entering input'': There is an error while entering numerator and denominator polynomials. Ensure that the entered format is correct. For example, a polynomial s²+3s+2 should be entered as s²+3*s+2.
2. ``Numerator and denominator are equal'': This error message is displayed when all poles and zeros of your transfer function cancel each other and you get a constant, memoryless system.
3. ``plzr() function couldnot handle your transfer function. See Scilab error code 60'': This is typically displayed when you have very high gains in the system (order of 1e10) and calculations are very sensitive. Reduce the maximum permissible gain of the rootlocus plot.
4. ``Warning! I need write permission in <directory name>. Please change your present working directory'':This warning is displayed when your present working directory is one in which you don't have a write permission. Set your appropriate working directory using "Settings->PWD".
5. ``Warning! Couldnot undo changes. No previous data available'': This warning is displayed when you don't have read /write permission in your present working directory. Solution is as above.
6. ``Sorry! I couldnot plot your step/ramp/impulse response. Due to numerical tolerances a pole zero cancellation has occured. Please reselect the point'': This error message is displayed when the closed loop transfer function is not proper (due to spurious pole-zero cancellations). Please reduce the maximum permissible gain in Settings->Rootlocus. or zoom the branch of the rootlocus before selecting the point
7. ``Sorry! I couldnot plot your frequency response. Due to numerical tolerances a pole zero cancellation has occured. Please reselect the point''. Same as above.
8. ``Error entering input. Input is not single valued'': While defining the arbitrary input, ensure that (1) input is piecewise linear (2) continuous (3) Single valued. If you don't ensure these, you will see this error. You will be prompted to select the response again.
9. ``Error Saving Plant. Ensure that you have write permissions'': You don't have write permission in your pwd.
10. ``Error loading Plant. Ensure that the file exists and you have read permission'': Either the file you are asking for doesn't exist or you don't have read permission. Change your pwd() or check the filename.