Sinclair SDV 6 Service Manual page 95

8.1.26 C77, C78 - Abnormal communication between IDU main control board and 1# function expansion
board, abnormal communication between IDU main control board and 2# function expansion board
Error display
Error impact
Error trigger
Error recovery
Possible cause
Troubleshooting
Figure 1 Wiring diagram of function expansion board, adapter board, and IDU main control board
Function expansion
board
92
Digital display
Faulty IDU: The fan continues running, and the EEV is closed. Other IDUs of the same system:
operate normally.
ODU of the same system: operate normally.
If the main control board of an IDU has lost communication with 1# function expansion board or 2#
function expansion board for 2 min
Automatic recovery
See the Troubleshooting section.
C77/C78
Note: The main control board of the IDU cannot be directly connected to the function expansion
board. Instead, an adapter board has to be used. See Figure 1 below:
Two-core
communication cable
(configured on site)
Panel, display box, and wired controller
Cause 1: The co mmuni cation
cable between th e function
expansion bo ard and th e
ada pte r bo ard becomes
disconnected or sho rt ci rcu ited
Cause 2: The co mmuni cation
cable between th e function
expansion bo ard and th e a dapter
boa rd h as become loose or is
connected to a wrong port
Cause 3: The IDU main control
boa rd i s damage d
Cause 4: The fun ction expansion
boa rd i s damage d
Adapter board
communication
(configured by
Display position
Replace th e
commu nicatio n cable an d
prop erly conn ect the
cable
Pro perly conn ect the
cables and ensure th ey
are conne cted to the right
ports
Replace th e main control
boa rd o f th e IDU
Replace th e function
expansion bo ard
IDU main control
board
Ten-core
cable
factory)