Speed Change Function - Mitsubishi Electric MELSEC iQ-R Series User Manual

Speed change function

The speed control function is used to change the speed during control to a newly designated speed at any time.
The new speed is directly set in the buffer memory, and the speed is changed by a speed change command ([Cd.15] Speed
change request) or external command signal.
During the machine home position return, a speed change to the creep speed cannot be carried out after deceleration start
because the proximity dog ON is detected. When the speed change function is enabled and the speed is slower than the
creep speed, the speed change is disabled and the speed accelerates to the creep speed after the proximity dog ON is
detected.
Control details
The following drawing shows the operation during a speed change.
[Md.40] In speed change
processing flag
Precautions during control
• At the speed change during continuous path control, when no speed designation (current speed) is provided in the next
positioning data, the next positioning data is controlled at "[Cd.14] New speed value". Also, when a speed designation is
provided in the next positioning data, the next positioning data is controlled at its "[Da.8] Command speed".
[Cd.14] New speed value
Designated speed in P2
Designated speed in P1
• When changing the speed during continuous path control, the speed change will be ignored if there is not enough distance
remaining to carry out the change.
• When the stop command was given to make a stop after a speed change that had been made during position control, the
restarting speed depends on "[Cd.14] New speed value".
V
Speed change
command
• When the speed is changed by setting "[Cd.14] New speed value" to "0", the operation is carried out as follows.
• When "[Cd.15] Speed change request" is turned ON, the speed change 0 flag ([Md.31] Status: b10) turns ON. (During interpolation control, the speed change
0 flag on the reference axis side turns ON.)
• The axis stops, but "[Md.26] Axis operation status" does not change, and the BUSY signal remains ON. (If a stop signal is input, the BUSY signal will turn
OFF, and "[Md.26] Axis operation status" will change to "stopped".) In this case, setting "[Cd.14] New speed value" to a value besides "0" will turn OFF the
speed change 0 flag ([Md.31] Status: b10), and enable continued operation.
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V
Speed changes to V2
V1
V2
0 1 0
Positioning control
P1
Speed change
command
Restart
command
Stop command
search engine
Operation during positioning by V1
Speed changes to V3
V3
t
1 0
Next control
P2
[a] When no speed designation (current speed) is provided
[b] When a speed designation is provided
[Da.8] Command speed
[Cd.14] New speed value
t
8.4 Functions to Change the Control Details
8 CONTROL SUB FUNCTIONS
8
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