Acpu Programming - Mitsubishi MELSEC-A A1SD71-S2 User Manual

6. PROGRAMMING
MELGfEGA
6.3 ACPU Programming
6.3.1 Data W a n d
wrtte
precautions
Data read from and written to the sequence program should be kept to a
minimum for optimum program scan time. The majority of the AlSD71
data must therefore be written to the buffer memory by the peripheral
device or the AD71TU.
The parameters and zero return data is checked at power on and when
the PC ready signal (Y2D) changes from OFF to ON.
Positioning data is checked immediately before
it
is processed. Any error
will cause the error signal
( X I B )
to switch on and, in most cases,
positioning to stop.
Pattern 00
Pattern 1 1
Pattern 01
[I1
Pattern 00
Dwell
P I
Positioning
Dwell
operation
I
I
I I
Dwell
I
I I
I
I
I
I
I
I I
I
I
I I
I I
Start
BUSY
I
l
d
I
d d
I
Data [I] check Data [2] check Data [3] check
Fig. 6.3 Positioning Data Check
An error is flagged if the total distance requested exceeds the upper
(or lower)
stroke limit when incremental position addressing is used.
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