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2 DATA COMMUNICATION USING PREDEFINED PROTOCOL
2.3 Packet
Non-conversion Variable
Use this element to send the data in the device memory of a CPU module or buffer memory as a part of a send packet, or
store a part of a receive packet to the device memory of a CPU module or buffer memory.
*1 Do not set local devices.
*2 Set within the device range specified in the following screen.
Project window [Parameter] CPU module type [CPU Parameter] [Memory/Device Setting]
Item Description
Element Name Set a name of the element.
Fixed Length/Variable
Length
Fixed Length Sends and receives the data whose length is fixed.
Variable Length • When sending: Specifies the data length at the time of the protocol execution and sends data.
• When receiving: Receives data whose data length is variable.
Data Length/
Maximum Data Length
Set the length of data to be transmitted and received.
(For the variable length data, set the maximum data length that can be specified to the data length storage area.)
The range is 1 to 2048.
Unit of Stored Data Lower Byte + Upper Byte • When sending: Sends each one word (2 bytes) data in the data storage area in the order of the lower
byte to the upper byte.
• When receiving: Stores the received data to the data storage area in the order of the lower byte to the
upper byte.
Lower Bytes Only • When sending: Sends only lower byte of data in the data storage area. C24 ignores data in the upper
byte.
• When receiving: Stores the received data in the only lower byte of the data storage area. C24 stores
00H in the upper byte.
Byte Swap Disable (lower -> upper)/
Enable (upper -> lower)
• When sending: When "Enable" is selected, sends data swapping the upper byte and lower byte by
word (2 bytes).
When "Unit of Stored Data" is "Lower Byte + Upper Byte" and "Data Length" is an odd number of bytes,
sends the upper byte at transmission of the last byte.
When "Unit of Stored Data" is "Lower Bytes Only" and "Data Length" is an odd number of bytes, sends
data without any byte swap at transmission of the last byte.
• When receiving: When 'Enable' is selected, receives data swapping the upper byte and lower byte by
word (2 bytes).
When "Unit of Stored Data" is "Lower Byte + Upper Byte" and "Data Length" is an odd number of bytes,
stores the last byte to the upper byte.
When "Unit of Stored Data" is "Lower Bytes Only" and "Data Length" is an odd number of bytes, stores
the last byte without any byte swap.
Data Storage Area
Specification
Specify a start device to store variable value.
■Settable devices
Internal user
*1*2
• Input (X)
• Output (Y)
• Internal relay (M)
• Latch relay (L)
• Link relay (B)
• Data register (D)
• Link register (W)
File register
*2
• File register (R,ZR)
Buffer memory
• G device (G)
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