Functions Related To Start; Pre-Reading Start Function - Mitsubishi Electric MELSEC iQ-FX5 User Manual

7.6

Functions Related to Start

A function related to start includes the "pre-reading start function". This function is executed by parameter setting or program
creation and writing.

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.
Controls
The pre-reading start function is performed by turning ON the positioning start signal with the execution prohibition flag
([Cd.183]) ON. 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
the following figure.)
■Operation example
[Cd.184] Positioning start
signal
[Cd.183] Execution
prohibition flag
[Md.141] BUSY signal
[Md.26] Axis operation status
Precautions during control
• The time required to analyze the positioning data is up to an operation cycle.
• After positioning data analysis, the system is put in an execution prohibition flag OFF waiting status. Any change made to
the positioning data in the execution prohibition flag OFF waiting status is not reflected on the positioning data. Change the
positioning data before turning ON the positioning start signal.
• The pre-reading start function is invalid if the execution prohibition flag is turned OFF between when the positioning start
signal has turned ON and when positioning data analysis is completed (Ta < start time, Ta: Reference to the above figure).
• The data No. which can be executed positioning start using "[Cd.3] Positioning start No." with the pre-reading start function
are No.1 to 600 only. Performing the pre-reading start function at the setting of No.7000 to 7004 or 9001 to 9004 will result
in the error "Outside start No. range" (error code: 19A3H).
• Always turn ON the execution prohibition flag at the same time or before turning ON the positioning start signal. Pre-
reading may not be started if the execution prohibition flag is turned ON during Ta after the positioning start signal is turned
ON. The pre-reading start function is invalid if the execution prohibition flag is turned ON after positioning start with the
execution prohibition flag OFF. (It is made valid at the next positioning start.)
7 CONTROL SUB FUNCTIONS
252
7.6 Functions Related to Start
V
ON
OFF
ON
OFF
ON
OFF
Position control Standby
Positioning
start timing
Ta
Positioning data
Execution prohibition flag OFF waiting
analysis
Analyzing
Operation cycle or less
Position control
t