The IP Express Setup control member hlq.CC2DEXEC($RMEXPR6) contains  a list of arguments, including MAXDUR.

For NetMaster r12 and r12.1, remarks for this argument are somewhat condensed:

A MAXDUR       2 Maximum duration of IP node generation.                   00840000

-                               Default is 2 minutes.                                                          00850000

-                               Range is 1 to 720    (ie 1min to 12hrs)                              00860000

But on NetMaster r11.7, remarks for the MAXDUR argument were more descriptive:

A  MAXDUR     15 Maximum duration of IP node generation   per              01030000

-                                 stack interface. After this time    expires,                          01040000

-                                 node address generation ends for one                               01050000

-                                 interface and begins for the next interface.                      01060000

-                                 Default is 15 minutes.                                                           01070000

-                                 Range is 1 to 720   (ie 1min to 12hrs)                                 01080000