Thanks, @Samir Khan ,for your reply.

Are there any plans to add support for delays to the Dynamic Systems package?

With everyone's help, I have managed to produce step responses, etc, by using the inttrans functions instead of the DynamicSystems functions.

Thanks @WD0HHU .

I've heard of it, but I have never used it. I would be interested in seeing how it is used and the benefits of it.

Thanks, @dharr for the insights on the convert(f,Heaviside).  That is very useful.  I also discovered the inverse convert(f, piecewise).

@C_R 

Thank you for your explanation.  I see what you mean. PhasePlot has just taken the opposite perspective since the phase always exceeds -180.  

As an experiment, I removed the doubling of the pole at zero and doubled the pole at two instead so that the phase ranged from -90 to -270.  This resulted in the range being what I expected, -90 to -270.

@Shaggy It looks like you've discovered some more interesting, but I would argue, undesirable behaviour.  Do you know what the mechanism is to raise it as an issue with Maplesoft?

@acer 

Wow, thank you for your help.  Your plot looks much better than mine!  I will give it a try.

@acer 

Thanks for your suggestion.

I tried that by using the MagnitudePlot and the PhasePlot funcions and then displaying the plots using the dualaxisplot.  While it did show both on one plot, it was pretty busy with the two curves overlying each other.  I'm not an expert in anything Maple, so can I ask if there is a way to separate the two plots vertically with dualaxisplot to mimic the output of BodePlot?

Do you know if Arrays of plots are supported in the plots:-display function in MapleFlow like it is in Maple?

@Kitonum 

Thanks for your help.

For my understanding, I would summarize the seq function support for units this way.

The seq function support units in the input parameters of a function and the return value but not in its iterand?

@Kitonum 

Thanks for that, but what if, for example, you have a function f(x), where x is expected to have units of length, and you have a problem where you want to mix metric and US Customary Units?

seq(f(x), x=1.0*Unit('m')..10.0*Unit('m'), 6.0*Unit('inch')), do you have to do the conversion yourself, seq(f(x*Unit('m')), x=1.0..10.0, 0.1524)?

@Thomas Richard 

On a related note, I thought I would use the modelica editor to create my component.  When I opened the Library Components->Thermal->FluidHeatFlow->Components, I discovered a few more components than in Maplesim: cylinder, OneWayValve and OpenTank.  Why aren't they available in MapleSim?

@Joe Riel Thanks for your help.

I now get this error.

When I assign the ports there is no temperature.

I have attached the file.

FluidMechanics_HeatedVessel.mw

I missed the MapleFlow webinar.  Is it going to be released as a recorded webinar?

Thank you for your help.  It works great.

I did a little experimentation and found that both fsolve and plot only work with the proc if a function was defined in their calling sequence as shown below.  So in order to avoid this issue in the future is there a simple way to trap the error within the proc or do you just have to use the explicit function definiton in the function call?