How to make a kind of memory in simulink?

Hello everybody,

I'm trying to make a model in simulink. This model have to simulate the outcoming flow of fluid from a tank. The flow is a variable, so in time it will and can be change (slider).

My problem is: I don't know how to built this kind of 'memory' in simulink. The new volume in the tank and the passed time have to set in a 'memory', so the same model can be used over en over again, in stead of building a model with dozen of 'copies', to simulate the process.

The example is attachment, it will show you how i've done it right now, but it isn't what i want. It's to complicated.

I hope somebody knows an answer/hint/trick or something to built a kind of memory for this problem.

Thanks

Answer 1

[Iain]

There are "memory" and integrator blocks built into simulink....

[Marcel Been]

I know there are standard memory blocks in simulink, but these don't work for this model. Or maybe I do something completly wrong.

[Iain]

An integrator might be what you want.

If you set it to have the initial value that is the volume of water in the tank. You can then feed into it, the flow rate of water entering/exiting the tank...

[Marcel Been]

Thanks, I'll try.

[Marcel Been]

I've tried, but it is not what i mean and need for my model.

I'll try to explane what's my problem.

• The begin volume = 30,000 litre.
• A slider will change the outcoming flow, this flow need to be change while the simulation is running.
• The simulationtime is for example 500 seconds.
• After 10 seconds the valve will open, the slider selects an outcoming flow of 100 litre/second
• 40 seconds later the outcoming flow will change to 250 litre/second
• this action shall repeat for another 10 times (everytime a different flow)
• I need a 'MEMORY' to remember the last volume, before changing the flow. Otherwise simulink use the new flow and multiplies it with the time.
• Also the flow has to be change while the simulation is running.
• I only want: 1 slider for controling the flow

Hopefully i made my problem any clearer. And i hope there is a sollution for this problem.