Timestamp too small in dc supply together with lm555

[margarett]

Hi all.

First of all, let me say that I am new to Multisim, and that I am working in a computer from a colleague at school.

Anyway, we are setting up a "more-or-less" simple circuit for our Electronics class, using some basic electronics. Since it is comprised of many parts, we managed to put them into Hierarchical Blocks.

It starts with a DC supply block, then an oscillator (with LM555) producing 1kHz, 50% duty cycle pulses that are fed into a fotodiode and a fototransistor, then a comparison block for comparison of the pulse height and so on...

We tested all blocks except DC supply, using "DC_POWER" components where needed. Then, those components should be replaced by our own HB. At it worked as expected.

As soon as we created the DC supply and added it to the project, immediatelly we got "Timestamp too small" convergence problems. Sometimes the convergence assistant says it can solve the problem, but all it does is make the error to occur later a little bit later, that's all...

If, again, we put back the "DC_POWER" components, then it works. We have been able to narrow the error to the first block, the oscillator. And if we, in that block, remove the LM555 (of course, no oscillation 🙂 ) then there is no error.

We are now on our second day around this problem, and no solution seems to be available...

Please take a look at the attached circuit, if possible. You should find the same errors. If you replace the dc supply part for a 12V DC_POWER, then it works fine.

Maybe there something really dumb that we are doing, but I cannot see what.

Thanks!

[Tayyab_R]

Hi Margarett,

I have made a modification to the circuit and now there is no error. One wire connection was missing.

Hope this helps