iocontrol - interacts with HAL or G-code in non-realtime
[EMCIO] EMCIO = io or EMCIO = iov2
I/O control handles I/O tasks like coolant, toolchange and E-stop. The signals are turned on and off in non-realtime with G-code or in the case of E-stop in HAL. I/O Control V2 (iov2) adds more toolchager support for communication with the toolchanger.
Whether io or iov2 is used can be chosen in the [EMCIO] section of the INI file.
See also https://linuxcnc.org/docs/html/config/iov2.html.
io(1), iov2(1)