开云体育

On Mon, Feb 24, 2025 at 05:38 PM, Tony Casey wrote:

By default, the .raw file is written with single precision; this option enables double precision (and approximately doubles the .raw file size).

Although that is true for voltages and currents, time values are always saved to the .raw file with double precision.? Time is special in that way.

?

What probably happened here is that the Waveform Cursor pop-up window itself displays the numbers with less precision than they are saved in the .raw file.

This is also true with .MEAS. The time points are printed in single precision in the logfile, by default. You can get double precision by adding .option measdgt=15. This is true whether or not you also use .option numdgt=15.

For example, to find the first falling value of 0, I added:

.MEAS T1 when V(test)=0 fall=1

..when analysing a 0.999Hz sine wave with .TRAN 1.1. By default the logfile was:

LTspice 24.0.12 for Windows
Circuit: * C:\users\tony\Desktop\LTspice\_Temp\Eewiz\MEAS_example.asc
Start Time: Tue Feb 25 10:09:09 2025
solver = Normal
Maximum thread count: 32
tnom = 27
temp = 27
method = modified trap
Direct Newton iteration for .op point succeeded.

t1: v(test)=0 AT 0.500501

Total elapsed time: 0.054 seconds.

After adding .option measdgt=15:

LTspice 24.0.12 for Windows
Circuit: * C:\users\tony\Desktop\LTspice\_Temp\Eewiz\MEAS_example.asc
Start Time: Tue Feb 25 10:10:33 2025
solver = Normal
Maximum thread count: 32
tnom = 27
temp = 27
method = modified trap
Direct Newton iteration for .op point succeeded.

t1: v(test)=0 AT 0.500500582598

Total elapsed time: 0.044 seconds.

Note: this option is sticky. It remains active for the session (until you close and restart LTspice), even if it is removed. Whether this is intended or not is not known. AFAIK, it is not documented.