12 - 45 
MELSEC-Q
12   CONTROL SUB FUNCTIONS 
 
[4]   Setting the speed change function using an external command 
signal 
The speed can also be changed using an "external command signal".  
The following shows the data settings and sequence program example for 
changing the control speed of axis 1 using an "external command signal". (In this 
example, the control speed is changed to "10000.00mm/min".) 
 
(1)  Set the following data to change the speed using an external command 
signal. 
(Use the start time chart shown in section (2) below as a reference, and set 
using the sequence program shown in section (3).) 
 
Buffer memory address
Setting item 
Setting 
value 
Setting details 
Axis 
1 
Axis 
2 
Axis 
3 
Axis 
4 
Pr.42
 
External command 
function selection 
1  Set "1: External speed change request".  62  212  362 512
Cd.8
 
External command 
valid 
1  Set "1: Validate the external command".  1505  1605  1705 1805
Cd.14
 
New speed value  1000000 Set the new speed. 
1514 
1515 
1614 
1615 
1714
1715
1814
1815
 
   Refer to Section 5.7 "List of control data" for details on the setting details. 
 
(2)  The following shows the speed change time chart. 
 
Pr. 42  External command function selection 
V
t
0
1
0
1
Md.40  In speed change processing flag
Cd. 14  New speed value 
1000000
0
1
0
Cd. 8   External command valid
Dwell time
BUSY signal
Error detection signal
PLC READY signal
Positionin
 start si
nal
Positioning complete signal
QD75 READY signal
Start complete signal
 [Y10]
[XC]
[X0]
[Y0]
[X10]
[X8]
[X14]
External command signal 
Fig. 12.29 Time chart for changing the speed using an external command signal