12 - 39 
MELSEC-Q
12   CONTROL SUB FUNCTIONS 
 
[2]   Wiring the hardware stroke limit  
When using the hardware stroke limit function, wire the terminals of the QD75 
upper/lower limit stroke limit as shown in the following drawing.  
(When "
Pr.22
Input signal logic selection" is set to the initial value) 
 
FLS
RLS
COM
24VDC
QD75
 
 
Note)  Connect the upper/lower limit switches to the directions of increasing and decreasing current 
feed values respectively.  When these switches are connected in wrong directions, the 
hardware stroke limit function does not operate properly and the motor does not stop. 
For "
 Pr.6 
 
Rotation direction setting", refer to "5.2.1 Basic parameters 1". 
 
Fig. 12.22 Wiring when using the hardware stroke limit 
 
[3]   Control Precautions 
(1)  If the machine is stopped outside the QD75 control range (outside the 
upper/lower limit switches), or if stopped by hardware stroke limit detection, 
the "OPR control", "major positioning control", and "high-level positioning 
control" cannot start. To carry out these types of control again, return the 
workpiece to the QD75 control range by a "JOG operation", "inching 
operation" or "manual pulse generator operation".  
(2) When "
Pr.22
Input signal logic selection" is set to the initial value, the 
QD75 cannot carry out the positioning control if FLS (upper limit signal) is 
separated from COM or RLS (lower limit signal) is separated from COM 
(including when wiring is not carried out). 
 
[4]   When the hardware stroke limit function is not used 
When not using the hardware stroke limit function, wire the terminals of the QD75 
upper/lower limit stroke limit as shown in the following drawing.  
When the logic of FLS and RLS is set to "positive logic" using "
Pr.22
Input 
signal logic selection", positioning control can be carried out even if FLS and RLS 
are not wired. 
(For details, refer to Section 13.4 "External I/O signal logic switching function".) 
 
QD75
FLS
RLS
COM
24VDC
 
Fig. 12.23 Wiring when not using the hardware stroke limit function 
(When "
Pr.22
 Input signal logic selection" is the initial value)