8 DEVICE ACCESS
8.1 Data to be Specified in Commands
71
8
*1 Page 71 Considerations when accessing long timer, long retentive timer, or long counter
*2 Page 71 Considerations when accessing long index register
*3 Page 71 Consideration when accessing file register
*4 Page 71 Consideration when accessing extended data register or extended link register
Considerations
■Devices that cannot be specified
• Devices which are not listed on the list cannot be specified by the command for device access of MC protocol.
• The available device type and device range are in accordance with the device specifications of access target module.
Specify the device that can be used for the access target module.
• Accessing a local device is not available.
• When accessing a device that cannot be specified, create a program etc. to copy a value and store the value temporarily in
the device that can be specified and access it.
• When a device can be assigned to a standard global label in GX Works3, even the device, to which a device code cannot
be specified, can be accessed by specifying the label name. (Page 125 LABEL ACCESS)
■Considerations when accessing long timer, long retentive timer, or long counter
Use any of the following commands.
*1 When reading data with a current value (LTN, LSTN) specified, the values of contacts and coils will be stored in the read data.
■Considerations when accessing long index register
Use a command to which double word access points can be specified.
• Page 99 Random read in word units (command: 0403)
• Page 106 Random write in word units (test) (command: 1402)
• Page 121 Register monitor data (command: 0801)
■Consideration when accessing file register
The file register specified to "Use File Register of Each Program" in "CPU Parameter" or "PLC parameter" of the CPU module
cannot be accessed from external devices.
If the file register of the CPU module is consist of multiple blocks, use the device code of the serial number access method.
To specify the file register with the serial number access method, refer to the manual of CPU module.
■Consideration when accessing extended data register or extended link register
If the access target CPU module does not support the access to the extended data register D65536 or later, and the extended
link register W10000 or later, replace the extended data register to the file register (ZR) and specify again. For the
replacement method, refer to the manual of Q/LCPU module.
I/O No. specified device U Page 442 Accessing module access devices
Page 444 Accessing CPU buffer memory access device
Module access device U\G Word Decimal G ABH G*** 00ABH
CPU buffer memory access device U3E\G Word Decimal G** 00ABH
U3E\HG Word Decimal HG** 002EH
Device Read Write
Long timer
Long retentive
timer
Contact LTS,
LSTS
Page 88 Batch read in word units (command: 0401)
*1
Page 110 Random write in bit units (test) (command:
1402)
Coil LTC,
LSTC
Current
value
LTN,
LSTN
Page 88 Batch read in word units (command: 0401)
Page 99 Random read in word units (command: 0403)
Page 106 Random write in word units (test) (command:
1402)
Long counter Contact LCS Page 88 Batch read in word units (command: 0401)
Page 92 Batch read in bit units (command: 0401)
Page 94 Batch write in word units (command: 1401)
Page 97 Batch write in bit units (command: 1401)
Page 110 Random write in bit units (test) (command:
1402)
Coil LCC
Current
value
LCN Page 88 Batch read in word units (command: 0401)
Page 99 Random read in word units (command: 0403)
Page 94 Batch write in word units (command: 1401)
Page 106 Random write in word units (test) (command:
1402)
Device For MELSEC-Q/L
series
For MELSEC iQ-R
series
Device name Symbol Type Notation ASCII Binary ASCII Binary