GE PACSystems RX7i - Page 180

Chapter 4. Ladder Diagram (LD) Programming
GFK-2950C February 2018 165
MOVE_FROM_FLAT Operands
Parameter
Description
Allowed Operands
Optional
Length (??)
Determines the number of UDT array elements to be filled
by copying data from reference memory to output Q.
1  Length  32,767
Constant
No
DC
Data coherency.
If True, memory being written to is locked, enabling
coherent copying of data from one Controller memory area
to another.
If False (default), data is copied normally from one
Controller memory area to another; that is without data
coherency.
▪ The input DC should be used only when using interrupt
blocks and is required only when the same memory is
used in more than one interrupt block, or in the main
program and an interrupt block.
▪ If DC is True, an interrupt block cannot preempt the
copy operation.
▪ If DC is False or not present, then interrupts can
preempt the copy.
▪ Using DC can impact interrupt latency if the amount of
data copied is large.
Data flow.
Yes
IN
Reference memory data being copied to UDT variable
elements in output Q as determined by the Length.
All except %S, symbolic, or
I/O variable.
No
Q
UDT variable or UDT array to which IN is copied.
Discrete or non-discrete
symbolic, discrete or non-
discrete I/O variable.
No
Example
A WORD variable mapped to %R1 is assigned to input IN and a value of 1 is assigned to Length. A
UDT variable or UDT array is assigned to output Q.
When MOVE_FROM_FLAT executes, n bytes of data are copied, starting at %R1 to a UDT variable or
UDT array, where n is the UDT array element length (in bytes). If a UDT array is assigned to output Q,
n bytes of data are copied to the first UDT array element.