Hi!
I don't know if is possible to get the status from a Device. Well, if it does not have a robot, how the UIM can get this kindle of information? This is a interesting question...
Anyway, for robots, I think you can use this call: http://{ip_ump}/rest/hubs/{domain}/{hub}/{robot}
And then you can see the value of the <status> tag.
Doc.: UIM Infrastructure Calls - CA Unified Infrastructure Management Probes - CA Technologies Documentation
Robot status descriptions: Robot Status descriptions
"0" (zero) = "Online/OK"
"1" (one) = "Maintenance"
"2" (two) or "3" (tree) = "Offline/Error"
"4" (four) = "Intermediate"
PS.: Sorry for my poor English.