Mitsubishi Electric MELSEC-Q Series - Functional Comparison between Qnas Series and Q Series

2 REPLACEMENT OF CPU MODULE
2 - 16
2.3.2 Functional comparison between QnAS series and Q series
: Available : Although available, specifications such as setting method partially differ. : Not available
Function Description
QnAS
series
Q series
Precautions for replacement Reference
Q2ASCPU
(S1)
Q2ASHCPU
(S1)
QnUCPU
Control
Constant scan
Executes the sequence program at the
constant time intervals regardless of the
processing time of the program.
 --
Latch (data
retention during
power failure)
Holds the data of devices when turning off
the power, resetting, and a momentary
power failure longer than the allowable
momentary power failure time occurs.

--
Remote RUN/
STOP
Remotely runs or stops the program
operations in the CPU module from external
switches or peripherals.

--
PAUSE
Stops operations while holding the output
status.
 --
Interrupt
processing
Executes the program that corresponds to
the cause when an interrupt cause occurs.

--
Display priority of
ERROR LED
Sets the ERROR LED on/off status at an
error.

Target errors vary by model, but there is no
functional difference.
-
File management
Manages such as parameters, sequence
programs, device comments, file registers as
files.

Memory configuration and data to be stored
differ between the QnAS series and Q series.
Section
2.4.1
Structured program
Selects a suitable execution type for
program application, and divides each
program by designer, process or others.
 --
I/O assignment
Assigns I/O points for each module
regardless of its mounted position.

When using a base unit with other than 8 slots,
set the number of slots with the parameter (I/O
assignment setting).
Section
2.4.4
Boot operation
(ROM operation)
Reads sequence programs stored in the
only or a memory card to the built-in memory
of the CPU module when the operating
status of the module is changed to RUN and
executes the read programs.

The Universal model QCPU, whose program
memory is a Flash ROM, does not have to
perform the ROM operation.
Section
2.4.1
Section
7.7.12
Data protection
function (system
protection,
keyword
registration/
password
registration)
Prevents unauthorized access from
peripherals to programs and comments in
the built-in memory of a CPU module or
memory cards.

The Q series prohibits each file from being read/
written by password registration, whereas the
QnAS series prohibit the parameters and
programs from being read/written to the user
memory by keyword registration.
Section
2.4.2
Initial device value
Sets an initial value of device memory, file
registers, and special function modules
when the CPU module is set from STOP to
RUN.

Memory configuration and data to be stored
differ between the QnAS series and Q series.
Section
2.4.1
Output status
setting at changing
from STOP to RUN
Sets the output (Y) status at the change from
STOP to RUN to reoutputting data before
STOP or outputting data after the operation
execution.

Resetting parameters is required to replace the
QnAS series with the Q series.
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