13 - 91
Chapter 13 Control Sub Functions
13.7.7 Pre-reading start function
The "pre-reading start function" does not start servo while the execution prohibition flag
is ON if a positioning start request is given with the execution prohibition flag ON, and
starts servo within operation cycle 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.
The "pre-reading start function" will be explained below.
[1] Controls
[2] Precautions during control
[3] Program examples
[1] Controls
The pre-reading start function is performed by turning ON the positioning start
signal with the execution prohibition flag ON, or by executing the dedicated
instruction (ZP.PSTRT1, ZP.PSTRT2, ZP.PSTRT3, and ZP.PSTRT4). However,
if positioning is started with the execution prohibition flag ON, the positioning data
is analyzed but servo start is not provided. While the execution prohibition flag is
ON, "
Md.26
Axis operation status
" remains unchanged from "5: Analyzing". The
servo starts within operation cycle after the execution prohibition flag has turned
OFF, and "
Md.26
Axis operation status
" changes to the status (e.g. position control,
speed control) that matches the control method. (Refer to Fig.13.46)
Signal
LD77MS2/LD77MS4
LD77MS16
Execution prohibition flag
Y14, Y15, Y16, Y17
Cd.183
Execution prohibition flag
[LD77MS4 operation example]
V
Positioning start signal
[Y10,Y11,Y12,Y13]
Execution prohibition flag
[Y14,Y15,Y16,Y17]
BUSY signal
[XC,XD,XE,XF]
OFF
OFF
ON
t
Ta
OFF
ON
ON
Md. 26 Axis operation
status
Positioning start timing
Positioning data
analysis
Execution prohibition flag OFF waiting
Standby
Analyzing
Position control
Position control
Operation cycle or less
(Note): Refer to Section 3.3 for input/output signal of LD77MS16.
Fig. 13.46 Operations of pre-reading start function
Summary of Contents for MELSEC-L Series
Page 2: ......
Page 30: ...MEMO ...
Page 70: ...2 10 Chapter 2 System Configuration MEMO ...
Page 83: ...3 13 Chapter 3 Specifications and Functions MEMO ...
Page 103: ...3 33 Chapter 3 Specifications and Functions MEMO ...
Page 107: ...3 37 Chapter 3 Specifications and Functions MEMO ...
Page 111: ...3 41 Chapter 3 Specifications and Functions MEMO ...
Page 115: ...3 45 Chapter 3 Specifications and Functions MEMO ...
Page 140: ...4 22 Chapter 4 Installation Wiring and Maintenance of the Product MEMO ...
Page 253: ...5 113 Chapter 5 Data Used for Positioning Control MEMO ...
Page 342: ...5 202 Chapter 5 Data Used for Positioning Control MEMO ...
Page 438: ...7 20 Chapter 7 Memory Configuration and Data Process MEMO ...
Page 440: ...MEMO ...
Page 485: ...9 25 Chapter 9 Major Positioning Control MEMO ...
Page 594: ...9 134 Chapter 9 Major Positioning Control MEMO ...
Page 624: ...10 30 Chapter 10 High Level Positioning Control MEMO ...
Page 656: ...11 32 Chapter 11 Manual Control MEMO ...
Page 690: ...12 34 Chapter 12 Expansion Control MEMO ...
Page 798: ...13 108 Chapter 13 Control Sub Functions MEMO ...
Page 866: ...14 68 Chapter 14 Common Functions MEMO ...
Page 884: ...15 18 Chapter 15 Dedicated Instructions MEMO ...
Page 899: ...16 15 Chapter 16 Troubleshooting MEMO ...
Page 1036: ...Appendix 88 Appendices MEMO ...
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