As of firmware update 7.50 update1 for the ACR7000 (controller, servo or stepper), DEFINES has been expanded to allow number.
For many users incorporating the axis number within the name, this can allow a shorter name and less typing when programming.
Note the number acts as a delimiter and the text before the number cannot be a reserved word (command) such as BIT or AXIS or MASTER and will cause an UNKNOWN COMMAND error. Users can see the list of reserved words by typing HELP in the terminal emulator or seeing the HELP command in the online help.
Version PMM 2.3 will flag these in the message window before downloading: