12 CONTROL SUB FUNCTIONS

MELSEC-Q

[2] Relation between the movement amount per pulse and speed

The following shows the relation of the "movement amount per pulse (A)" to the command speed and actual speed. The command speed is the speed commanded by each control, and the actual speed is the actual feedrate.

Command speed = V (The command frequency at that time is represented by "f")

Actual speed = V' (The command frequency at that time is represented by " f' ")

 

 

Relation of the command speed and actual speed

 

 

 

 

 

 

1) Movement amount per pulse < 1

V < V' (f < f')

 

The actual speed becomes faster than the

 

command speed.

 

 

 

 

 

 

 

 

 

 

2) Movement amount per pulse = 1

V = V' (f = f')

 

The actual speed is the same as the command

 

speed.

 

 

 

 

3) Movement amount per pulse > 1

V > V' (f > f')

 

The actual speed becomes slower than the

 

command speed.

 

 

 

 

 

V

 

 

Actual speed V'

 

 

 

 

 

 

 

1)

 

Command speed V

 

2)

 

 

 

 

 

 

 

 

3)

 

 

 

 

 

 

t

 

 

 

 

 

Fig. 12.9 Relation of the movement amount per pulse to the command speed and actual speed

12 - 16

Page 492
Image 492
Mitsubishi Electronics QD75P, QD75D user manual Relation between the movement amount per pulse and speed, Actual speed