12 - 34
MELSEC-Q
12 CONTROL SUB FUNCTIONS
12.5 Functions to change the control details
Functions to change the control details includ e the "speed change function", "override
function", "acceleration/deceleration time c hange function" and "torque change
function". Each function is executed by param eter setting or sequence program
creation and writing.
Both the "speed change function" or "overr ide function" change the speed, but the
differences between the functions are shown bel ow. 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 ex cludes
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 th e speed during control to a newly
designated speed at any time.
The new speed is directly set in the buffer m emory, and the speed is changed by a
speed change command ( Cd.15 Speed change request) or external command sign al.
During the machine OPR, a speed change to the cr eep speed cannot be carried out
after deceleration start because the near poi nt dog ON is detected.
The details shown below explain about the "spe ed 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 a n external command signal
[1] Control details
The following drawing shows the operation dur ing 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