# Simulation problem

**URL:** <https://community.factoryio.com/t/simulation-problem/2191>\
**Category:** Support\
**Created:** [June 25, 2023, 10:20am UTC](https://community.factoryio.com/t/simulation-problem/2191 "2023-06-25T10:20:30Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![yashw4854](https://avatars.discourse-cdn.com/v4/letter/y/ac8455/32.png) [@yashw4854](https://community.factoryio.com/u/yashw4854)\
**Post date:** [June 25, 2023, 10:20am UTC](https://community.factoryio.com/t/simulation-problem/2191/1 "2023-06-25T10:20:30Z")

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Hello,  
I am facing one problem while doing simulation  
The problem is whenever I use Normally closed equipments like stop button, emergency button, and photo reflective sensor then while doing simulation signal from this device doesn’t remain ON instead it is flickering like On then OFF then ON  
I am using Siemens plcsim edition in factory io and tiaportal  
So is this problem of tiaportal of factory io ?  
Have anyone face same problem ?

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**Author:** ![hojaje3610](https://avatars.discourse-cdn.com/v4/letter/h/b4bc9f/32.png) [@hojaje3610](https://community.factoryio.com/u/hojaje3610)\
**Post date:** [June 27, 2023, 8:35am UTC](https://community.factoryio.com/t/simulation-problem/2191/2 "2023-06-27T08:35:13Z")

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Yes I also have this same problem. In my case I am using a real Siemens PLC. I also have the trouble that inputs are toggeling TRUE/FALSE, although in Factory IO its True

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**Author:** ![brunovgr](https://dub1.discourse-cdn.com/flex017/user_avatar/community.factoryio.com/brunovgr/32/12_2.png) [@brunovgr](https://community.factoryio.com/u/brunovgr)\
**Post date:** [June 27, 2023, 10:08am UTC](https://community.factoryio.com/t/simulation-problem/2191/3 "2023-06-27T10:08:07Z")

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Hi @yashw4854 and @hojaje3610

This issue may be related to the following [topic](https://community.factoryio.com/t/siemens-inputs-not-working/34).

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**Author:** ![hojaje3610](https://avatars.discourse-cdn.com/v4/letter/h/b4bc9f/32.png) [@hojaje3610](https://community.factoryio.com/u/hojaje3610)\
**Post date:** [June 29, 2023, 12:58pm UTC](https://community.factoryio.com/t/simulation-problem/2191/4 "2023-06-29T12:58:40Z")

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correct, that topic solved the basic io true false toggleing :D. Now for the next question. I have the same issue with the safety inputs of a 1214F plc.