To provide RAS(reliability, availability and serviceability) display system, device and method capable of quickly executing display processing or holding uniqueness among data of each group to be displayed.

In an operation state monitoring device 30, a reading part 31 acquires RAS data from a programmable controller(PC) 40 in accordance with a user's request and stores the acquired RAS data in a RAS data storing part 32. The storing part 32 temporarily stores the RAS data 32a acquired from the PC 40 by the reading part 31. An updating date stoiring part 34 stores the updating date data of the RAS data 32a stored in the storing part 32. In the PC 40, a comparing part 43 compares updating date data included in a request command outputted from the reading part 31 with updating date data stored in a management table storing part 44 and judges whether both the data coincide with each other or not. At the time of non-coincidence, a transmission part 42 transmits RAS data stored in a RAS storing part 41 and the updating date data stored in the storing part 44 to the monitoring device 30.