4 - 4 
MELSEC-Q
 
4   INSTALLATION, WIRING AND MAINTENANCE OF THE PRODUCT 
 
(2)   The LED display indicates the following operation statuses of the QD75 and axes. 
 
QD75
M
4
RUN
ERR AX4
AX3
AX2
AX1
 QD75M4
 
 
Display  Attention point  Description  Display  Attention point  Description 
RUN
ERR
AX1
AX2
AX3
AX4
 
RUN is OFF. 
Hardware failure, 
watch dog timer 
error 
RUN
ERR
AX1
AX2
AX3
AX4
 
AX1 (or other 
axis) illuminates. 
The 
corresponding 
axis is in 
operation. 
RUN
ERR
AX1
AX2
AX3
AX4
 
RUN illuminates. 
ERR is OFF. 
The module 
operates 
normally. 
RUN
ERR
AX1
AX2
AX3
AX4
 
ERR flashes. 
AX1 (or other 
axis) flashes. 
An error occurs 
on the 
corresponding 
axis. 
RUN
ERR
AX1
AX2
AX3
AX4
 
ERR illuminates.  System error 
RUN
ERR
AX1
AX2
AX3
AX4
 
All LEDs 
illuminate. 
Hardware failure 
RUN
ERR
AX1
AX2
AX3
AX4
 
AX1 to AX4 are 
OFF. 
The axes are 
stopped or on 
standby. 
  
   
The symbols in the Display column indicate the following 
statuses: 
    : Turns OFF.  : Illuminates.  : Flashes. 
 
(3)   
The interface for each QD75 is shown below:
 
 
QD75M1                QD75M2                 QD75M4 
QD75M1 QD75M2
AX1
AX2
AX1
RUN
ERR
AX2
AX1RUN
ERR
AX1
 QD75M1
 QD75M2
QD75M4
AX1
AX2
AX3
AX4
RUN
ERR AX4
AX3
AX2
AX1
 QD75M4