# Is it safe to use modbus functions in secondary program?

**URL:** <https://forum.universal-robots.com/t/is-it-safe-to-use-modbus-functions-in-secondary-program/24855>\
**Category:** Robot Communication\
**Created:** [November 7, 2022, 11:23am UTC](https://forum.universal-robots.com/t/is-it-safe-to-use-modbus-functions-in-secondary-program/24855 "2022-11-07T11:23:47Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![csaba.mucsi](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.universal-robots.com/csaba.mucsi/32/277_2.png) [@csaba.mucsi](https://forum.universal-robots.com/u/csaba.mucsi)\
**Post date:** [November 7, 2022, 11:23am UTC](https://forum.universal-robots.com/t/is-it-safe-to-use-modbus-functions-in-secondary-program/24855/1 "2022-11-07T11:23:47Z")

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Hello,

In several modbus functions - for example `modbus_get_signal_status` - there is a boolean parameter called “is\_secondary\_program”  
The URScript Manual says:  
is\_secondary\_program: A boolean for internal use only. **Must be set to False**

Is it safe to use modbus functions from the secondary program?  
If yes: should the is\_secondary\_program parameter be set to True even if the documentation says “Must be set to False” ?

Thanks  
Csaba