How to export data logging in Simcape simulation by second?

Hello,

I tried to run this Lithium Battery Cell - One RC-Branch Equivalent Circuit. My run time is 36000s but the data logging only has 1150 data. I adjusted model setting solver with max stepsize is 1 but does not help.

Please help! Thank you so much in advance

openExample('simscape/LithiumBatteryCellOneRCBranchEquivalentCircuitExample')

[Thanh]

this is the out put after I ran the model

only 1150 data

Answer 1

[TED MOSBY]

Hi Thanh,

Missing data points can be due to using a "variable‐step solver" due to which Simulink only saves points at the time steps the solver actually takes. Simply setting “Max step size = 1” may not guarantee you will get 1s–spaced data, because the solver may still choose fewer (larger) steps, especially if the system is not changing rapidly.

To get a uniform output every 1s (or any spacing you want), you can do the following:

Use a fixed‐step solver

• In Model Settings → Solver, change Type to “Fixed‐step” (instead of “Variable‐step”).
• Set Solver (e.g., ode4) and Fixed step size to 1s.
• This ensures Simulink advances exactly in 1s increments and will produce 36001 points over 0–36000s.
• Under Additional parameters in Data Import/Export, make sure the Limit data points to last is large enough or unchecked if you want all data.

Use a “To Workspace” Block

You can manually place a To Workspace block in your model and double-click it to configure:

• Sample time: Set it to 1.0 (seconds), so it forces the block to sample at every 1s.
• Limit data points to last: Make sure this is large enough or unchecked if you want all data.

If you just need a time series at a consistent 1s interval, the simplest approach is to pick a fixed‐step solver with step size = 1s.

Hope it helps!

Answer 2

[Yifeng Tang]

First thing to check, whether you are limiting the number of data points to keep. I suspect so, as your tout variable has length of 1000.

It's possible to define a time vector where you want the output to be sampled at. See below.

This applies to logged Simulink signals only. If you use a sensor to measure Simscape values and convert to Simulink signal and log, this still applies. If you are getting data out of simlog, I think the easiest way is to do an interp1 in a post-processing script.

I actually disagree with the "fixed-step" solver approach mentioned in another answer. Variable-step solver is usually faster and more accurate. Interpolating in the region where a larger time step is taken by the variable step solver should be safe. In addition, the model may not give accurate results with the 1sec fixed step.