6 - 70 
MELSEC-Q
 
6   SEQUENCE PROGRAM USED FOR POSITIONING CONTROL 
 
6.5.6 Stop program 
The axis stop signal [Y4, Y5, Y6, Y7] or a stop signal from an external source is used 
to stop the control. 
Create a program to turn ON the axis stop signal [Y4, Y5, Y6, Y7] as the stop program. 
 
The process for stopping control is explained below. 
Each control is stopped in the following cases. 
 
(1)   When each control is completed normally. 
(2)   When the Servo READY signal is turned OFF. 
(3)   When the PLC READY signal is turned OFF. 
(When a stop error such as "parameter error" or "watch dog timer error" occurs in 
PLC CPU.) 
(4)   When an error occurs in QD75. 
(5)   When control is intentionally stopped  
(Stop signal from PLC CPU turned ON, stop signal from peripheral devices) 
 
The stop process for the above cases is shown below. 
(Excluding item (1) above "When each control is completed normally".) 
 
[1] Stop process 
 
Stop process 
OPR control  Manual control 
Stop cause 
Stop 
axis 
M code 
ON 
signal 
after stop 
Axis 
operation 
status 
(
Md.26
) 
after 
stopping 
Machine 
OPR 
control 
Fast OPR 
control 
Major 
positioning 
control 
High-level 
positioning 
control 
JOG/ 
Inching 
operation 
Manual 
pulse 
generator 
operation 
Forced stop 
Servo READY OFF 
• Servo amplifier 
power supply 
OFF 
• Servo alarm 
• Emergency stop 
of PLC CPU
 
Each 
axis 
No 
change 
During 
error 
Servo OFF or free run 
 
Fatal stop  
(Stop group 1) 
Hardware stroke 
limit signal ON 
Each 
axis 
No 
change 
During 
error 
Deceleration stop/sudden stop  
(Select with "
Pr.37
Sudden stop group 1 sudden stop 
selection". 
Deceleration 
stop 
Error occurs in 
PLC CPU 
No 
change 
PLC READY 
signal OFF 
Turns 
OFF 
Emergency stop  
(Stop group 2) 
Error in test 
mode 
All axes 
No 
change 
During 
error 
Delegation stop/sudden stop  
(Select with "
Pr.38
Sudden stop group 2 sudden stop 
selection". 
Deceleration 
stop 
Axis error 
detection (Error 
other than stop 
group 1 or 2) 
Relatively safe 
stop  
(Stop group 3) 
"Stop" input from 
peripheral device 
Each 
axis 
No 
change 
During 
error 
"Stop signal" ON 
from external 
source 
Intentional stop 
(Stop group 3) 
"Axis stop signal" 
ON from PLC 
CPU 
Each 
axis 
No 
change 
During 
stop 
(during 
standing 
by) 
Deceleration stop/sudden stop  
(Select with "
Pr.39
Sudden stop group 3 sudden stop 
selection". 
Deceleration 
stop