9 MAJOR POSITIONING CONTROL

MELSEC-Q

Current feed value during 2-axis speed control

The following table shows the " Md.20 Current feed value" during 2-axis speed

control corresponding to the " Pr.21 Current feed value during speed control" settings. (Note that the reference axis setting values are used for parameters.)

"

 

Current feed value during speed

 

 

 

Pr.21

 

 

 

 

Md.20

Current feed value

 

 

control" setting

 

 

 

 

 

 

0: Do not update current feed value

The current feed value at speed control start

is maintained.

 

 

 

 

 

1: Update current feed value

The current feed value is updated.

2: Zero clear current feed value

The current feed value is fixed at 0.

Speed

In speed control

Speed

 

 

t

Current feed value during speed control start is maintained

In speed control

Speed

In speed control

t

 

t

Current feed value is updated

 

0

(a) Current feed value not updated

(b) Current feed value updated

(c) Current feed value zero cleared

Restrictions

(1) Set "Positioning complete" in "

Da.1

Operation pattern". An axis error

"Continuous path control not possible (error code: 516)" will occur and the operation cannot start if "continuous positioning control" or "continuous path control" is set.

("Continuous positioning control" and "continuous path control" cannot be set in speed control.)

(2) Set the WITH mode in "

Pr.18

M code ON signal output timing" when using

an M code. The M code will not be output, and the M code ON signal will not turn ON if the AFTER mode is set.

(3) Set the "reference axis speed" in "

Pr.20

Interpolation speed designation

method". An "Interpolation mode error (error code: 523)" will occur and the operation cannot start if a composite speed is set.

(4)When either of two axes exceeds the speed limit, that axis is controlled with the speed limit value. The speeds of the other axes are limited at the ratios of

"Da.8

Command speed".

(Examples)

 

 

 

Axis

 

 

 

 

 

 

Axis 1 setting

Axis 2 setting

Setting item

 

 

 

 

 

 

 

 

 

 

Pr.8

Speed limit value

4000.00mm/min

5000.00mm/min

 

 

 

 

 

 

 

 

 

 

 

 

 

Da.8

Command speed

8000.00mm/min

6000.00mm/min

 

 

 

 

 

 

With the settings shown above, the operation speed in speed control is as follows.

Axis 1: 4000.00 mm/min (Speed is limited by

Pr.8

).

Axis 2: 3000.00 mm/min (Speed is limited at an ratio of an axis 1 command speed to an axis 2 command speed).

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Mitsubishi Electronics QD75D, QD75P user manual Current feed value during 2-axis speed control, Command speed Examples