Absolutely possible via PU.
I actually posted this awhile back:
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You can also do this with the Probe Utility against the robot . Use 'maint_until' and specify how long it should be in maintenance mode for, leave 'until' empty (this is an epoch number), and specify how many seconds in the 'for' parameter.
For example:
pu -u administrator -p xxxxxxxx /"full path to robot"/controller maint_until for 120 until ""
Remember to always include all parameters and leave the "blank" ones in the end.
The call back for the controller is:
maint_until (until, for)
To enter maintenance mode:
Specify either the 'until' value, which is a time value representing the time in seconds since the Epoch (00:00:00 UTC, January 1, 1970) or the 'for' value which is the time in seconds you want the robot to stay in maintenance mode.
To leave maintenance mode:
Use the same call but do not specify neither 'until' nor 'for'.
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Here is the original thread with some other options - good luck!
http://forum.nimsoft.com/t5/General/Maintenance-mode/m-p/2774#M1822
Dustin