# Logging, Custom Profile savename prefix **URL:** \ **Category:** EMU PRO\ **Created:** [April 23, 2024, 3:40pm UTC](https://community.ecumaster.com/t/logging-custom-profile-savename-prefix/1202 "2024-04-23T15:40:14Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![SamiN](https://dub1.discourse-cdn.com/flex013/user_avatar/community.ecumaster.com/samin/32/208_2.png) [@SamiN](https://community.ecumaster.com/u/SamiN)\ **Post date:** [April 23, 2024, 3:40pm UTC](https://community.ecumaster.com/t/logging-custom-profile-savename-prefix/1202/1 "2024-04-23T15:40:14Z")
If I use custom profile, does it change “on the fly” or does it stops base profile logging and start new log file? If it starts new log, is it possible to have prefix for save file name (like c\_xxxxxxx). I was thinking case when i want general stuff logged all the time at low Hz and when some params. are met, then some more channels at higher frequency. Prefix then could help to find quickly right log file from USB stick. ---
**Author:** ![Jan\_Matlag\_ECUMASTER](https://dub1.discourse-cdn.com/flex013/user_avatar/community.ecumaster.com/jan_matlag_ecumaster/32/1466_2.png) [@Jan\_Matlag\_ECUMASTER](https://community.ecumaster.com/u/Jan_Matlag_ECUMASTER)\ **Post date:** [April 23, 2024, 4:28pm UTC](https://community.ecumaster.com/t/logging-custom-profile-savename-prefix/1202/2 "2024-04-23T16:28:34Z")
It changes on the fly. Change can occur every 40 ms. It does NOT create a new log file. ---
**Author:** ![SamiN](https://dub1.discourse-cdn.com/flex013/user_avatar/community.ecumaster.com/samin/32/208_2.png) [@SamiN](https://community.ecumaster.com/u/SamiN)\ **Post date:** [April 23, 2024, 4:33pm UTC](https://community.ecumaster.com/t/logging-custom-profile-savename-prefix/1202/3 "2024-04-23T16:33:07Z")
ok, thanks. Then I just need to use functions to add markers 🙂