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MELSEC-Q
4 SETTINGS AND PROCEDURES PRIOR TO OPERATION
(1) LED display list
ERR.
CH2
CH1
SD
RD
NEU.
SD
NEU.
RD
RUN
QJ71C24N
ERR.
CH2
CH1
SD
RD
NEU.
SD
NEU.
RD
RUN
QJ71C24N-R2
ERR.
CH2
CH1
SD
RD
NEU.
SD
NEU.
RD
RUN
QJ71C24N-R4
Compatible protocol
CH LED Display contents On/flashing Off
MC Non-procedural Bidirectional
RUN Normal operation display Normal Faulty or reset
—
ERR Error display (
1) Error has occurred Normal
Valid
NEU
(
3)
Neutral status on the CH1
side display ( 2)
Waiting for MC command
message to be received
MC command message
being received
Valid Invalid (Off)
SD
Transmission status
display
Data being transmitted Data not transmitted
CH1
RD Reception status display Data being received Data not received
Valid
NEU
(
3)
Neutral status on the CH2
side display ( 2)
Waiting for MC command
message to be received
MC command message
being received
Valid Invalid (Off)
SD
Transmission status
display
Data being transmitted
MC command message
not transmitted
CH2
RD Reception status display Data being received
MC command message
not received
Valid
1 This LED comes on when an error occurs at Q series C24 hardware or during data communication.
2 This LED displays the data communication status via MC protocol. (see chapter 10.)
On: Waiting for the command message to be received from the external device.
Off: Processing the command message received from the external device.
3 This LED can be made valid also when "GX Developer connection" (0H) is specified in communication
protocol setting.