AH500 Module Manual 
10-64 
extension rack 
connection fails. 
3.  Check if the bus communication cable length 
exceeds the maximum transmission distance.   
(Refer to section 10.3.3. The system may no longer 
keep stable if the maximum distance is exceeded.) 
4.  Check if all modules on the rack are normal. 
5.  Check if the extension rack connected to 
AHRTU-DNET is connected normally.