9 - 12 
MELSEC-Q
 
9   MAJOR POSITIONING CONTROL 
 
(4)   Speed switching  
       (Refer to "
Pr.19
 Speed switching mode".) 
 
(a)  Standard speed switching mode 
 
1)  If the respective command speeds differ in the "positioning data 
currently being executed" and the "positioning data to carry out 
the next operation", the machine will accelerate or decelerate 
after reaching the positioning point set in the "positioning data 
currently being executed" and the speed will change over to the 
speed set in the "positioning data to carry out the next operation". 
2)  The parameters used in acceleration/deceleration to the 
command speed set in the "positioning data to carry out the next 
operation" are those of the positioning data to carry out 
acceleration/deceleration. 
Speed switching will not be carried out if the command speeds 
are the same.  
 
OFF
ON
OFF
ON
OFF
ON
OFF
ON
11 11 11 01
00
V
Dwell time
Da. 1 O
peration pattern 
Start complete signal
BUSY signal
Positioning complete signal
Positioning start signal
Positioning
[Y10, Y11, Y12, Y13]
[X10, X11, X12, X13]
Dwell time
[XC, XD, XE, XF]
[X14, X15, X16, X17]
 
Fig. 9.4 Operation for the standard speed switching mode 
 
3)  Speed switching condition 
If the movement amount is small in regard to the target speed, the 
current speed may not reach the target speed even if 
acceleration/deceleration is carried out. In this case, the machine 
is accelerated/decelerated so that it nears the target speed.  
If the movement amount will be exceeded when automatic 
deceleration is required (Ex. Operation patterns "00", "01", etc.), 
the machine will immediately stop at the designated positioning 
address, and a "insufficient movement distance warning (warning 
code: 513)" will occur.