When I Googled it, I found this on Page 52 of this document.
FIX−RAM
Using B&R Automation Studio™ (software configuration), you can
configure a part of User RAM to behave like User ROM during a
COLD RESTART. This memory area is called FIX RAM.
Objects stored in FIX RAM are not deleted during a COLD RESTART.
COLD RESTART boot mode corresponds to the first time a processor
is initialized. The operating system is restarted and all RAM data
(except objects stored in FIX RAM) is deleted.