Chapter 4. Ladder Diagram (LD) Programming
166
PACSystems* RX7i, RX3i and RSTi-EP CPU Programmer's Reference Manual
GFK-2950C
4.8.15
Move to Flat
MOVE_TO_FLAT instruction copies data from symbolic or I/O variable
memory to reference memory. MOVE_TO_FLAT copies across
mismatched data types for an operation such as a Modbus transfer.
MOVE_TO_FLAT provides optional data coherency by locking the
reference memory being written to during the copy operation. This
allows data to be copied coherently when accessed by multiple logic
threads (i.e. interrupt blocks). Note that copying large amounts of data
with coherency enabled can increase interrupt latency.
Notes:
■
The Data Coherency (DC) input 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.
Copying Arrays and Array Elements
The Length determines the number of UDT array elements to be copied to the reference memory of
the variable assigned to output Q.
Example:
If the value 6 is assigned to Length, there should be a UDT array of at least six elements
assigned to input IN. When logic executes,
n
bytes of data are copied from the UDT array elements to
the reference memory of the variable assigned to output Q, where
n
is the length of the UDT array
element (in bytes) times six.
Summary of Contents for PACSystems RSTi-EP
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