9MAJOR POSITIONING CONTROL

(3)Speed handling

MELSEC-Q

(a)Continuous path control command speeds are set with each positioning data.

The QD75 then carries out the positioning at the speed designated with each positioning data.

(b)The command speed can be set to "–1" in continuous path control.

The control will be carried out at the speed used in the previous positioning data No. if the command speed is set to "–1". *1

(The "current speed" will be displayed in the command speed when the positioning data is set with a peripheral device. The current speed is the speed of the positioning control being executed currently.)

1)The speed does not need to be set in each positioning data when carrying out uniform speed control if "–1" is set beforehand in the command speed.

2)If the speed is changed in the previous positioning data when "–1" is set in the command speed, the operation can be continued at the new speed.

3)An error "no command speed" (error code: 503) occurs and positioning cannot be started if "–1" is set in the command speed of the first positioning data at start.

 

 

[Relation between the command speed and current speed]

 

 

*1

P1

P2

P3

P4

P5

*2

Speed

P1

P2

P3

P4

P5

Speed

 

3000

 

 

 

 

 

 

3000

 

 

 

 

 

2000

 

 

 

 

 

 

2000

 

 

 

 

 

1000

 

 

 

 

 

 

1000

 

 

 

 

 

Da. 7 Command speed

1000

3000

-1

-1

-1

Md. 36 Current speed

1000

3000

3000

3000

3000

Da. 7 Command speed 1000 3000

-1

-1

-1

Md. 36 Current speed 1000 3000

3000

3000

3000

The current speed is changed even if the command speed is not reached in P2.

POINTS

(1)In the continuous path control, a speed variation will not occur using the near-pass function when the positioning data is switched (Refer to Section 12.3.3 "Near-pass function").

(2)The QD75 holds the command speed set with the positioning data, and the latest value of the speed set with the speed change request as the " Md.27 Current speed". It controls the operation at the "current speed" when "-1" is set in the command speed.

(Depending on the relation between the movement amount and the speed, the feedrate may not reach the command speed value, but even then the current speed will be updated. *2)

(3)When the address for speed change is identified beforehand, generate and execute the positioning data for speed change by the continuous path control to carry out the speed change without requesting the speed change with a sequence program.

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Mitsubishi Electronics QD75D, QD75P user manual Speed handling, Speed 3000 2000 1000