Once you set the time units in a model, you can't really change the units through normal means. However, you can manually change the model units by changing the values in the tree at model/Tools/ModelUnits. To change to seconds, just change /Time/Name to "second", /Time/Abbreviation to "s", /Time/Multiple to 1, and /Time/Plural to "seconds".
However, this will not change the inherent nature of your model. All it will do is change the way certain values are labeled (and, when you next open the model, it will scale default values in the library so they are based on that new time unit, so when you drop new objects into the model, their default values will be based on the model's units). This means that if you defined your process time in a processor as exponential(0, 10) "minutes", when you subsequently change the model units to seconds, all you've changed is the label of what your processor's process time means, so now your processor's process time is exponential(0, 10) "seconds". This means, if your model was initially created in meters, i.e. operators you created were about 2 "meters" tall, then when you change that model unit to feet, all the operators in your model will now be 2 "feet" tall. Granted any new operators you create after reopening that model will be the proper 6 "feet" tall because, again, the library defaults are scaled to a model's units. But existing operators in the model will remain the same size, in "length units", they were created with. So if the xsize of an operator is 2 before the change, it will be 2 after the change. You've only changed your interpretation label for that 2 value from "meters" to "feet".
Under the hood FlexSim only sees "time units". It thinks exponential(0, 10, 0) time units, and nothing else. You, the modeler, are the one who labels that exponential(0, 10) with, "this is in minutes", and you do that when you create a new model. Because of all of this, we discourage changing the model units by inhibiting it in the user interface.
You may say, well, that's kind of a stupid way to go. But properly changing a model's units is much harder than you might think. For example, what if you have, in your model, some code somewhere that says something like:
Code:
double secondsToWork = exponential(0, 600);
double secondsToWait = normal(300, 5);
double totalTime = secondsToWork + secondsToWait;
senddelayedmessage(current, totalTime, current);
In order to properly convert that code from being based on seconds to using minutes, FlexSim would have to somehow search for and change that code to:
Code:
double minutesToWork = exponential(0, 10);
double minutesToWait = normal(5, 5);
double totalTime = minutesToWork + minutesToWait;
senddelayedmessage(current, totalTime, current);
That would be essentially impossible. Another option is to require our users, when they enter values representing times, to use functions instead of constants where time units are involved:
Code:
double timeToWork = exponential(minutes(0), minutes(10));
double timeToWait = normal(minutes(5), minutes(5));
double totalTime = timeToWork + timeToWait;
senddelayedmessage(current, totalTime, current);
But here the problem is we just haven't trained our users to do that, and to me it's a lot of extra work we'd be putting on our users, just to enable them to change model units mid-stream.
So, it is what it is.
Changing Model Units
Simulation Clock