Read And Write Device Memory; Considerations; Data To Be Specified In Command - Mitsubishi Electric MELSEC IQ-R series Reference Manual

18.4

Read and Write Device Memory

This section explains the specification content and examples of the request data and the response data when reading and
writing device memory.
For the message formats other than request data and response data, refer to the following sections.
Page 391 Message Format, Page 391 Details of Setting Data
To read and write the extended file register, use the commands dedicated to the extended file register.
Page 418 Read and Write Extended File Register

Considerations

Considerations when reading/writing data to module other than ACPU module
■Accessible devices
Only the devices with the same names that exist in ACPU can be accessed within the device range of AnACPU.
The following devices cannot be accessed from the external devices
• Added devices
• Latch relay (L) and step relay (S)
• File register (R)
■Special relays and special registers
Special relays and special registers can be accessed within the following range.
• Access SM1000 to SM1255 by specifying M9000 to M9255.
• Access SD1000 to SD1255 by specifying D9000 to D9255.
■Universal model QCPU
Use the Universal model QCPU with a serial number whose first five digits are '10102' or later.
When the module with the serial number whose first five digits are '10101' or earlier, access using 3E frame or 4E frame.
When accessing the built-in Ethernet port of the CPU module, refer to the following manual.
 QnUCPU User's Manual (Communication via Built-in Ethernet Port)

Data to be specified in command

Device codes and device numbers
The settings of each device when reading/writing device memory can be performed using device code and device number as
shown in the following figure.
Specify the device to be accessed by a device code and a device number.
The order of data differs depending on the ASCII code or binary code.
ASCII code
Device code Device number
(4 digits) (8 digits)
■Data communication in ASCII code
• Device code: Convert the numerical value to 4-digit ASCII code (hexadecimal), and send it from the upper digits.
• Device number: Convert the numerical value to 8-digit (hexadecimal) ASCII code, and send it from the upper digits.
Binary code
Device number Device code
(4 bytes) (2 bytes)
18 COMMUNICATING USING 1E FRAMES
18.4 Read and Write Device Memory
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