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MELSEC-Q
 
12   CONTROL SUB FUNCTIONS 
 
[4]   Precautions during software stroke limit check 
(1)  A machine OPR must be executed beforehand for the "software stroke limit 
function" to function properly.  
(2)  During interpolation control, a stroke limit check is carried out for the every 
current value of both the reference axis and the interpolation axis. Every 
axis will not start if an error occurs, even if it only occurs in one axis.  
(3)  During circular interpolation control, the "
Pr.12
 Software stroke limit upper 
limit value"/"
Pr.13
 Software stroke limit lower limit value" may be 
exceeded. 
In this case, a deceleration stop will not be carried out even if the stroke limit 
is exceeded. Always install an external limit switch if there is a possibility the 
stroke limit will be exceeded. 
 
Arc address ( Da. 7 ) 
End point address ( Da. 6 )
Axis 1
Axis 1 stroke limit
Deceleration stop not carried out
Starting address
  The software stroke limit check is carried out for the following addresses
  during circular interpolation control. (Note that " Da. 7  Arc address" is carried 
  out only for circular interpolation control with sub point designation. 
Current value/end point address ( Da. 6 )/arc address ( Da. 7 )
Axis 2
Example
 
 
(4)  If an error is detected during continuous path control, the axis stops 
immediately on completion of execution of the positioning data located right 
before the positioning data in error. 
 
Md. 26
Axis operation status
No.10 No.11 No.12 No.13
Immediate stop at
error detection
No.10
P11
No.11
P11
No.12
P11
No.13
P11
No.14
P01
Controlling position
Error occurring 
Positioning data 
 • If the positioning address of positioning data No. 13 is outside the software stroke limit range,
   the operation immediately stops after positioning data No. 12 has been executed. 
Example