# How to write the transient analysis ltspice directive with a stop time and start saving data time?

How to include 0.9m start saving data in spice directive?

.trans 1m

Right click with the mouse on the text .trans 1m and change it in the dialog box as shown below.

The LTspice directive becomes .tran 0 1m .9m

Explanation of the preceeding zero:
The syntax is: .TRAN <Tstep> <Tstop> [Tstart [dTmax]] [modifiers]
If Tstart or dTmax is specified, Tstep must has to be specified as well. Tstep is the plotting increment for the waveforms but is also used as an initial step-size guess. LTspice uses waveform compression, so this parameter is of little value and can be omitted or set to zero.

• unfortunately, im using the mac version of ltspice which doesn't have the edit simulation command menu, am I right? – www Oct 19 at 20:00
• @www That's why I added the new spice directive as well. I was already thinking it had to be someting like that. Why would someone ask something very basic for LTspice under Windows? – Huisman Oct 19 at 20:03
• So if the stop is 1m and start saving data is 0.9m, the directive is .trans 0 1m .9m But when I checked the result, why it still shows the data before 0.9m? – www Oct 19 at 20:04
• In case the help file doesn't work under Mac, you might be interested in: ltwiki.org/LTspiceHelpXVII/LTspiceHelp.html .. do check the whole site, it's interesting :) – Huisman Oct 19 at 20:07
• @www Note that the plot window always starts at 0 (and not at e.g. 0.9 msec). Are you sure the window shows the data before this 0.9 ms? An easy way to verify this is adding a Behavioral Voltage Source with V=time and plot that result as well. The voltage should be 0.9mV at t=0s. – Huisman Oct 19 at 20:14