Mitsubishi QD75P1N User Manual

12 - 97
MELSEC-Q
12 CONTROL SUB FUNCTIONS
12.7.7 Pre-reading start function
The "pre-reading start function" does not output pulses while the execution prohibition
flag is ON if a positioning start request is given with the execution prohibition flag ON,
and starts outputting pulses within 1.3ms (QD75P
N/QD75D N) or 3ms
(QD75P
/QD75D ) after OFF of the execution prohibition flag is detected. The
positioning start request is given when the axis is in a standby status, and the
execution prohibition flag is turned OFF at the axis operating timing. This shortens the
virtual start time. The QD75 normally takes 1.5 to 2.0ms (QD75P
N/QD75D N) or 6
to 7ms (QD75P
/QD75D ) from when it receives a positioning start request until it
starts pulse output (start time). Some systems often need the start time to be
shortened. This "pre-reading start function" can improve the tact time of the system.
The "pre-reading start function" will be explained below.
[1] Control details
[2] Control precautions
[3] Program examples
[1] Control details
The pre-reading start function is performed by turning ON the positioning start
signal [Y10, Y11, Y12, Y13] with the execution prohibition flag [Y14, Y15, Y16,
Y17] ON, or by executing the dedicated instruction (ZP.PSTRT1, ZP.PSTRT2,
ZP.PSTRT3, ZP.PSTRT4). However, if positioning is started with the execution
prohibition flag ON, the positioning data is analyzed but pulse output is not
provided. While the execution prohibition flag is ON, "
Md.26
Axis operation
status" remains unchanged from "5: Analyzing". Pulse output starts within 1.3ms
(QD75P
N/QD75D N) or 3ms (QD75P /QD75D ) after the execution
prohibition flag [Y14, Y15, Y16, Y17] has turned OFF, and "
Md.26
Axis
operation status" changes to the status (e.g. "Position control", "Speed control")
that matches the control system. (Refer to Fig. 12.49)
V
ON
OFF
OFF
OFF
ON
ON
t
Ta
OFF
ON
ON
Positioning start
signal
[Y10,Y11,Y12,Y13]
Execution
prohibition flag
[Y14,Y15,Y16,Y17]
BUSY signal
[XC,XD,XE,XF]
Md.26
Axis operation
status
Position control Position controlStandby
Positioning
data analysis
Execution prohibition flag
OFF waiting
Analyzing
Positioning start timing
Start time
1.3ms or less (QD75P N/QD75D N) or
3ms or less(QD75P /QD75D )
Fig. 12.51 Operations of pre-reading start function

Mitsubishi QD75P1N Specifications

General

Brand	Mitsubishi
Model	QD75P1N
Category	Controller
Language	English