# Problem running Test18.fst in Simulink by Changing TMax using FAST\_8.16

**URL:** <https://forums.nlr.gov/t/problem-running-test18-fst-in-simulink-by-changing-tmax-using-fast-8-16/1530>\
**Category:** Computer-Aided Engineering Software Tools\
**Created:** [January 6, 2017, 8:42am UTC](https://forums.nlr.gov/t/problem-running-test18-fst-in-simulink-by-changing-tmax-using-fast-8-16/1530 "2017-01-06T08:42:52Z")\
**Posts on this page:** 1\
**Showing post:** 50

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**Author:** ![Jason.Jonkman](https://dub1.discourse-cdn.com/nrel/user_avatar/forums.nlr.gov/jason.jonkman/32/3086_2.png) [@Jason.Jonkman](https://forums.nlr.gov/u/Jason.Jonkman)\
**Post date:** [April 7, 2017, 3:15pm UTC](https://forums.nlr.gov/t/problem-running-test18-fst-in-simulink-by-changing-tmax-using-fast-8-16/1530/50 "2017-04-07T15:15:59Z")

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Dear David,

As I said before, you can’t directly get M, C, K, and F because FAST v8 linearization does not output M, but you can get I, [M^-1]\*C, [M^-1]\*K, and [M^-1]\*F. The latter, [M^-1]\*F, is available in the B matrix instead of the A matrix. This first-order form should also be amendable for controls design.

Best regards,

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