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Issue Details

When I run my simulation, I get a pop-up window with the following message:

"A simulation error has occurred. Would you like to run the Convergence Assistant to attempt to resolve this problem automatically?"

Solution

Simulation errors can arise for different reasons. To resolve these issues, first let the Convergence Assistant attempt to solve the problem. If it is not able to fix it, look for the following causes:

• Floating components [i.e. parts with unconnected pins]; these can go into the SPICE matrix, even if they are not being used, but can cause difficulties later.
• Extremely tiny resistor values; these enter the SPICE matrix as 1/resistance, creating large calculations. Some native components, like the SPST switch, have low resistance values. Try the following modifications in the circuit:
  • Use the GROUND component to add a clear reference to the circuit.
  • Increase the minimum resistance of the component.
  • Use a different component that provides the same functionality.
• Direct voltage source across P-N junctions; this usually happens with LEDs and indicator components.
• Parallel voltage sources and inductors.

If you are still getting convergence issues after checking for the above, your next step is to adjust tolerances. You can change the tolerances by doing the following:

In summary, the conversation is about a problem with simulating a circuit in Multisim, with the user encountering an error during transient analysis. They mention trying different models of opamps and ask for suggestions on how to fix the issue. The expert suggests cutting the voltage in half or adding a resistor to the output, and asks if the user has checked for a stable dc operating point or tried AC analysis. The user then reveals that they had not connected the power supplies to the opamp correctly, and the problem is solved.

• Sep 26, 2015

• 1

Hi. I have problem simulating this circuit in Multisim:

[LTSpice]

Here is scheme from Multisim:

When I run transient analysis, I got this: -- Checking SPICE netlist for Design3 - Saturday, September 26, 2015, 10:58:03 AM -- \======= SPICE Netlist check completed, 0 error[s], 0 warning[s] ======= Transient time point calculation did not converge Simulation canceled Any idea what's wrong? Thanks in advance

• Sep 26, 2015

• 2

I tried different models of opamp and I got same error. Here is my version of software:

• Sep 27, 2015

• 3

cut v4 and v1 in half or set to 0 just to see what happens. Add a 10k to ground on the output to see what happens.

Do you get a stable dc operating point?

Have you tried AC analysis?

• Sep 27, 2015

• 4

Solved, I didn't connect power supplies to op amp correctly :]

Related to [Multisim] Transient time point calculation did not converge

1. Why did my transient time point calculation not converge?

There are several possible reasons for this. It could be due to a complicated circuit with many non-linear components, inaccurate initial conditions, or incorrect simulation settings. It may also be caused by numerical issues such as step size or convergence criteria.

2. How can I troubleshoot this issue?

First, check your simulation settings and make sure they are appropriate for your circuit. You can also try reducing the step size or changing the convergence criteria. If the issue persists, try simplifying your circuit or breaking it down into smaller sections to identify the problematic component.

3. Can I manually adjust the initial conditions?

Yes, you can manually adjust the initial conditions by right-clicking on the component and selecting "Advanced" and then "Edit Initial Conditions". Here, you can enter the desired values for the initial conditions.

4. Is there a way to improve the convergence of my simulation?

Yes, there are a few things you can try to improve convergence. First, make sure that your components are accurately modeled and have proper parameters. You can also try increasing the simulation time to allow more time for convergence. Additionally, if you are using non-linear components, try using smaller time steps or changing the convergence criteria.

5. Can I avoid this issue in the future?

It is possible to avoid this issue by carefully designing your circuit and selecting appropriate simulation settings. It is also important to use accurate component models and check for any errors or warnings in the simulation log. However, in some cases, convergence issues may still occur due to the complexity of the circuit.