I ran into something the other day and have been working with tech support on, but thought I might get some answers here.
Four layer board, two inner layers set to planes (and shield) FR4 material.
In the Setup - cross section tool, when I try to calculate the trace width based on a given impedance and stack up, the impedance is always 60 ohms. For example, I open the cross section tool and select Show Single Impedance. The default impedance shows as 60 ohms. If I try to change it to 50 ohms by manually editing the cell, it resets to 60 as soon as I click out of the cell.
If I try to change it by using the drop down boxes at the bottom of the window; Layer Type - Conductor; Material 1oz cu; Field set to - Impedance; Value Set to - 50; then select "Update Fields", nothing happens.
We tried multiple things yesterday. I even sent the board file to tech support and it works just fine for them (figures.....)
I tried it on a different computer at my home office and the impedance is displayed in exponential format, not in ohms.
A couple of screen shots:
oldmouldy said:OK, another thought. Any chance at all that the User Preference for the materials.dat locations has changed or that you have a custom, but incomplete, materials.dat in the local directory. Possibly the required values are not in the materials.dat being found and the calculations bail out from there. I have found that the first materials.dat found is used in isolation and not merged with other materials.dat files, so an incomplete one could potentially wreck things.
Tech support sent me a new materials.dat file that we tried in a few locations with no effect.