| 摘要 |
PURPOSE:To reduce a communication cost for transmitting data between a building group management device and the respective building management devices and to reduce a load. CONSTITUTION:Latest communication exchange time is stored(2d) whenever communication is exchanged between the building group management device 2 and the respective building unit management devices, the building unit management device having no communication exchange record after preceding abnormality presence or absence check time is picked-up when the abnormality presence or absence check time of the respective building unit management devices is due and an abnormality presence or absence check part checks (2c) the presence or absence of abnormality only in the building unit management device having no communication exchange recording for more than fixed time. Thus, abnormality presence or absence is not checked in the building unit management device which is obviously normal and has no necessity of an abnormality presence or absence check so that the load of a system for checking abnormality presence or absence is reduced and a charge for using a line is reduced. |
