the time in my simulation "freezes"

[ehudg]

as i'm running the sim, after a short period of time the measurement instruments are comming to a hault. for example: the scope instead of showing a particular continuos value, comes to a hault and shows small changes in the signal with no respect to the time.

[lacy]

Mine has done that also. Usually it occurs because of either the way the circuit is hooked up or the way the settings are in the simulator.

To isolate what it is your circuit would have to be posted if you can do that.

[ehudg]

the simulated circuit is a op-amp based pwm. that configuration did work practicaly when i've built it.

[lacy]

This is a good one. It would appear to me to be something about the motor causing a problem. I can disconnect the motor and it works fine. I am not sure what it is about the motor that is causing this, but I continue looking into it.

[lacy]

O.K. Here's a solution. This is probably not the solution you would have hoped for. It seems that one side of the Motor has to be grounded while the other side recieves the signal. This is the only way I could get it to stop freezing. This is all I could come up with unless there is a problem with the Motor in the software.

You might also want to drop the Maximum Timesteps down to .001. This seems to make the waveform from the motor appear correct.

I hope this helps some.

Message Edited by lacy on 08-20-2007 11:22 AM

[lacy]

I have a question for you. How did you get your motor looking like it does in your schematic?

[lacy]

I have still been investigating your circuit. The first post I made works, but I have come up with another solution that is probably more to what you are looking for. The only change made is to take the LED from where it is now and place it across the Power MOS. It could be that this was acting as a short across the Motor and that is why it was freezing. I will post both versions for you to look at and see which one you like better.

The first one is with the motor grounded and the second is more like tour first schematic except for the LED

[ehudg]

first of all sorry for the late reply and thank you very much for the files you attached.

second (regarding your question) - the motor was sent to me by technical support team after "repairing" my circuit.

[ehudg]

i have another question: i can't say i entirely understand how this motor (the animated one) works - what exactly do you measure with the scope attached to the motor's rotor?

[lacy]

It is supposed to be RPM represented by a voltage, but I am still not clear on how that exactly works.