LG RCWW Operation & Maintenance Manual page 112

8. TROUBLESHOOTING
112
(-)
(-) (+)
Controller board
Figure 67 Pressure sensor
Digital input signal is not checked in the controller.
In the case that the no voltage contact point signal input is properly made to the controller's digital input side but con-
troller finds it as abnormal or there is no change in all of the digital input signals, it is because of the defective con-
nection of I/O board power connector or no communication between I/O board and main board.
Check communication line connection status between I/O board and main board, and if there is no problem, short-cir-
cuit the connector of the wiring among the controller digital inputs, which are not activated, to COM connectors(23,
24) of controller I/O board to check whether the LED LAMPs corresponding to the I/O board input connector are
lighted.
Select "Menu Key" –"System Information" –"I/O input" of the controller display and short-circuit/open problem con-
nectors with COM connector to see whether input status changes to "ON"/"OFF".
Measure DC voltage between COM connector of the controller digital input and the digital input of which the wire
was released. Check whether the measured value is 18V.
If there is no problem, connect them again and check whether it works normally.
If the corresponding board main power and communication are normal but I/O input still does not work, the board
needs to be replaced.
Check by referring to the flow chart and tester connection diagram below.
Current sensor
(+)
- Place at DC30mA
- Measured value
should be between
4~20mA
(-) (+)
(-) (+)
(-) (+)
Figure 68 Current sensor measuring circuit
- Place at DC30mA
- Measured value
should be between
4~20mA
Current sensor