9
CJ-series Features Section 1-2
Program Replacement
during Operation
It is now possible to replace the entire user program in the CPU Unit from the
Memory Card during operation. In this way, it is possible to switch PLC opera-
tion without stopping the PLC.
Easy Backups It is now possible to back up all data (user programs, parameters, and I/O
memory) to the Memory Card by pressing the Memory Card power supply
switch. In this way, if a malfunction arises, it is possible to back up all data in
the CPU Unit at the time without using a Programming Device.
Specialized Instructions Simplify Programming
Text String Instructions The text string instructions allow text processing to be performed easily from
the ladder program. These instructions simplify the processing required when
creating messages for transmission or processing messages received from
external devices with the protocol macro function.
Loop Instructions The FOR(512), NEXT(513), and BREAK(514) instructions provide a very
powerful programming tool that takes up little program capacity.
Index Registers Sixteen Index Registers are provided for use as pointers in instructions. An
Index Register can be used to indirectly address any word in I/O memory. The
CJ-series PLCs also support the auto-increment, auto-decrement, and offset
functions.
The Index Registers can be a powerful tool for repetitive processing (loops)
when combined with the auto-increment, auto-decrement, and offset func-
tions. Index Registers can also be useful for table processing operations such
as changing the order of characters in text strings.
Table Data Processing Instructions
Stack Instructions
A region of I/O memory can be defined as a stack region. Words in the stack
are specified by a stack pointer for easy FIFO (first-in first-out) or LIFO (last-in
first-out) data processing.
Range Instructions
These instructions operate on a specified range of words to find the maximum
value or minimum value, search for a particular value, calculate the sum or
FCS, or swap the contents of the leftmost and rightmost bytes in the words.
.OBJ
PLC operation
Replacement
Processing of text string
data
External device with
standard serial port
Pointer
Stack region
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