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MELSEC-Q
12 CONTROL SUB FUNCTIONS
12.5 Functions to change the control details
Functions to change the control details include the "speed change function", "override
function", "acceleration/deceleration time change function" and "torque change
function". Each function is executed by parameter setting or sequence program
creation and writing.
Both the "speed change function" or "override function" change the speed, but the
differences between the functions are shown below. Use the function that corresponds
to the application.
"Speed change function"
•
The speed is changed at any time, only in the control being executed.
•
The new speed is directly set.
"Override function"
•
The speed is changed for all control to be executed. (Note that this excludes
manual pulse generator operation.)
•
The new speed is set as a percent (%) of the command speed.
12.5.1 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 OPR, a speed change to the creep speed cannot be carried out
after deceleration start because the near point dog ON is detected.
The details shown below explain about the "speed change function".
[1] Control details
[2] Precautions during control
[3] Setting the speed change function from the PLC CPU
[4] Setting the speed change function using an external command signal
[1] Control details
The following drawing shows the operation during a speed change.
V
V1
V2
V3
t
Speed changes to V2.
Operation during
positioning by V1.
Speed changes to V3.
Md. 40 In speed change processing flag
Fig. 12.22 Speed change operation