Filter
Top Products
9 - 3 9 - 3
MELSEC-Q
9 TROUBLESHOOTING
9.1.2 When communication with all slave nodes cannot be performed (using the master
function)
Communication with all slave nodes cannot be
performed (the NS LED is flashing in green or lit in red)
Is the mode switch set between
0 and 2 or between 6 and 8?
No
Reset by setting the mode switch between
0 and 2 or between 6 and 8.
Yes
Is the communication cable securely
connected to the QJ71DN91 connector?
Connect the communication cable securely.
Is the network power turned ON?
Turn ON the network power.
Is the communication speed
the same in all stations?
Set the same communication speed in
all stations.
Is a terminal resistor connected?
Are there any duplicate slave station
numbers with the QJ71DN91?
Set non-duplicate station numbers.
Are the parameters written?
Do the created parameters match
with the hardware configuration of the
actual slave station?
Create and write correct parameters.
Connect a terminal resistor.
Is the refresh request Y11 set to ON?
Set the refresh request to ON.
Is an error code generated?
Take an action according to the error code.
Check the entire network status such as noise
and installation.
Yes
Yes
No
No
No
No
Yes
Yes
No
Yes
Yes
No
No
No
Yes
Yes
Yes
No