Section 7 Ethernet/Ip Telegram Composition - Hach SC4500 User Manual

Figure 9 Industrial Ethernet Interface web page

Section 7 EtherNet/IP Telegram composition

The format of the EtherNet/IP tags can be integer (2 bytes), unsigned integer (2 bytes) or float
(4 bytes).
The data transmission between the SC4500 controller and the PLC is done with an Input/Output
connection. The Input/Output connection is bidirectional. The originator (PLC or HMI) sends data to
the target (SC4500 controller) and the target sends data to the originator. This type of connection is
also called Exclusive Owner connection or Controlling connection.
The input data size is the data sent from the SC4500 to the PLC. The input data size is calculated
based on the tags configured in the controller. The output data size is the data sent from the PLC to
the SC4500. The output data size is 0 bytes if there are no inputs selected and 32 bytes for each
8 selected inputs from the PLC. The maximum capacity of the Telegram is 768 bytes for input data
and 128 bytes for output data.
The input and output size are configured in the Outputs > EtherNet/IP > Module definition view of
the PLC.
For example:
• 5 tags selected: tag 0 (2 bytes), tag 1 (2 bytes), tag 2 (2 bytes), tag 3 (4 bytes) and tag 4 (4 bytes).
Total 14 bytes.
Note: Use the drag and drop function to change the elements on the Telegram list. Push and hold on the element
and move the device or tag to the new position. Make sure to update the PLC configuration accordingly after the
elements are moved.
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