Anybus Communicator Modbus plus, Руководство пользователя

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Frame Objects 42
Doc.Id. SCM-1200-093
Anybus Communicator for Modbus Plus
Doc.Rev. 3.01
7.5 Data Object
Data Objects are used to represent raw data as follows:
• Produce/Query Transactions
The specified data block is forwarded from the higher level network to the subnetwork.
• Consume/Response Transactions
The specified data block is forwarded from the subnetwork to the higher level network.
To specify the properties of the object, select it in the Navigation Section and enter the desired settings
in the Parameter section as follows:
7.6 Variable Data Object
Note: Only one Variable Data Object is permitted for each transaction.
This object is similar to the Data Object, except that it has no predefined length. Instead, an End or
Length-character specifies the size of the data block as follows:
• Produce/Query Transactions
The specified data block will be forwarded from the higher level network to the subnetwork. The
control system must supply an End- or Length-character in order for the gateway to know the
size of the data block.
The End- or Length-character itself may either be forwarded to the subnetwork or discarded.
• Consume/Response Transactions
The specified data block is forwarded from the subnetwork to the higher level network. The
End- or Length-character will be generated by the gateway automatically (if applicable).
The End- or Length-character itself may either be forwarded to the higher level network or dis-
carded.
Parameter Description
Byte Swapping • No Swapping
No swapping is performed on the data
• Swap 2 bytes
A, B, C, D becomes B, A, D, C
• Swap 4 bytes
A, B, C, D becomes D, C, B, A
Data Length The length of the data block, in bytes. In case of a Response or Consume transaction, incom-
ing messages where the data size differs from the value specified here will be discarded. Max-
imum data length allowed for one frame is 300 bytes.
Data Location The location of the data block in the internal memory buffer
4 bytes of data
(Variable Data Object)
Length Character
0x04 Data
Data of arbitrary length
(Variable Data Object)
End Character
0x00 Data