Mitsubishi Electric MELSEC-L LD75D, Руководство пользователя

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CHAPTER 6 PROGRAM USED FOR POSITIONING CONTROL
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CHAPTER 6
PROGRAM USED FOR POSITIONING
CONTROL
6.1
Precautions for Creating Program
The common precautions to be taken when writing data from the CPU module to the LD75 buffer memory are
described below.
When diverting any of the program examples introduced in this manual to the actual system, fully verify that there are
no problems in the controllability of the target system.
(1) Reading/writing the data
Setting the data explained in this chapter (various parameters, positioning data, block start data) should be set
using GX Works2.
When set with the program, many programs and devices must be used. This will not only complicate the
program, but will also increase the scan time.
When rewriting the positioning data during continuous path control or continuous positioning control, rewrite the
data four positioning data items before the actual execution.
If the positioning data is not rewritten before the positioning data four items earlier is executed, the process will be
carried out as if the data was not rewritten.
(2) Restrictions to speed change execution interval
Provide an interval of 100ms or more when changing the speed or performing override function with the LD75.
(3) Process during overrun
Overrun is prevented by the setting of the upper/lower stroke limits with the detail parameter 1.
However, this applies only when the LD75 is operating correctly.
It is recommended to create an external circuit including a boundary limit switch to ensure the whole system
safety as follows: the external circuit powers OFF the motor when the boundary limit switch operates.
(4) System configuration
Unless particularly designated, the program for the following system is shown in this chapter and subsequent. In
the program, the unit of "0 (mm)" is set for the basic parameter 1.
Refer to

Page 239, Section 6.2 for the application of the devices to be used.