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2 skip function, Melsec-q, 1] control details – MITSUBISHI ELECTRIC Mitsubishi Programmable Logic Controller QD75D User Manual

Page 539: 2] precautions during control

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MELSEC-Q

12 CONTROL SUB FUNCTIONS

12.7.2 Skip function

The "skip function" is used to stop (deceleration stop) the control of the positioning

data being executed at the time of the skip signal input, and execute the next

positioning data.

A skip is executed by a skip command (

Cd.37

Skip command) or external command

signal.

The "skip function" can be used during control in which positioning data is used.

The details shown below explain about the "skip function".

[1] Control details

[2] Precautions during control

[3] Setting the skip function from the PLC CPU

[4] Setting the skip function using an external command signal

[1] Control details

The following drawing shows the skip function operation.

BUSYsignal

V

Deceleration by
skip signal

Start of the
next positioning

ON

OFF

OFF

OFF

OFF

ON

ON

ON

Positioning

Positioning start signal

Positioning complete signal

Skip signal

t

[XC, XD, XE, XF]

[Y10, Y11, Y12, Y13]

[X14, X15, X16, X17]

Fig. 12.37 Operation when a skip signal is input during positioning control

[2] Precautions during control

(1) If the skip signal is turned ON at the last of an operation, a deceleration stop

will occur and the operation will be terminated.

(2) When a control is skipped (when the skip signal is turned ON during a

control), the positioning complete signals (X14, X15, X16, X17) will not turn
ON.

(3) When the skip signal is turned ON during the dwell time, the remaining dwell

time will be ignored, and the next positioning data will be executed.

(4) When a control is skipped during interpolation control, the reference axis

skip signal is turned ON. When the reference axis skip signal is turned ON,
a deceleration stop will be carried out for every axis, and the next reference
axis positioning data will be executed.

(5) The M code ON signals (X4, X5, X6, X7) will not turn ON when the M code

output is set to the AFTER mode (when "1: AFTER mode" is set in "

Pr.18

M code ON signal output timing").

(In this case, the M code will not be stored in "

Md.25

Valid M code".)

(6) The skip cannot be carried out by the speed-position and position-speed

switching control. It is processed in the same manner as in the speed
control.