# "Encountered 5 consecutive,overruns on core0, terminating" in RTBox

**URL:** <https://forum.plexim.com/t/encountered-5-consecutive-overruns-on-core0-terminating-in-rtbox/1812>\
**Category:** RT Box\
**Tags:** plecs, error, rt-box\
**Created:** [February 20, 2025, 7:12am UTC](https://forum.plexim.com/t/encountered-5-consecutive-overruns-on-core0-terminating-in-rtbox/1812 "2025-02-20T07:12:06Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Camberlam](https://avatars.discourse-cdn.com/v4/letter/c/f07891/32.png) [@Camberlam](https://forum.plexim.com/u/Camberlam)\
**Post date:** [February 20, 2025, 7:12am UTC](https://forum.plexim.com/t/encountered-5-consecutive-overruns-on-core0-terminating-in-rtbox/1812/1 "2025-02-20T07:12:06Z")

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Hello:  
I used four npc half-bridge power modules with a transformer to create a npc-dab, the offline simulation is working however when i applied to the RTBox it shows the error like topic. shoud i use other components rather than transformer or there’s other recommendations to solve this issue? thank you.  
[combineDABrtbox2-2.plecs](https://forum.plexim.com/uploads/short-url/a4mCfntujbaB4GUVYhoDM2SHdDf.plecs) (144.3 KB)

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**Author:** ![EnriquePLECS](https://dub1.discourse-cdn.com/flex006/user_avatar/forum.plexim.com/enriqueplecs/32/2276_2.png) [@EnriquePLECS](https://forum.plexim.com/u/EnriquePLECS)\
**Post date:** [February 20, 2025, 2:31pm UTC](https://forum.plexim.com/t/encountered-5-consecutive-overruns-on-core0-terminating-in-rtbox/1812/2 "2025-02-20T14:31:36Z")

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You are not actually using a transformer, you are using a coupled inductor, you could use the ideal transformer instead, since it will be simpler to compute and it lets you adjust the terminal voltages.

If I use a dedicated task frame to run the DAB in a different CPU core, and I increase your discretization step size to 15us. The model runs, you can see that there are overruns for the first simulation step sizes, after that the model is calculated  
[combineDABrtbox2-2.plecs](https://forum.plexim.com/uploads/short-url/akaoS1FqRZWBSLqjDpj6nLpun3t.plecs) (99.2 KB)  
under 10us. It seems you are using an RTBox 3 so I would try first to run the model on the FPGA, to decrease the simulation step size.