EtherNet/IP: Explicit Server Setup - LS Electric XGB PLC from AutomationDirect

If our XGB PLC has an EIPT module installed, we can set up an Explicit Ethernet connection. The XEM CPU is capable of being both an Explicit Client that sends data or an Explicit Server that receives data. To set up the PLC as an Explicit Server, we first must configure the EIPT module and the peer-to-peer connection. These are both covered in a separate video. Once we have the EIPT IP settings and the peer-to-peer connection configured, we can make the PLC available as an Explicit Server. This access is very similar to setting the PLC up as an Implicit Target or Adapter. To do this, we go to the project window on the left side of the screen and maximize the “P2P 03” subheading and then double-click on EIP Channel. This opens the “Channel Setting” pop-up window. We will use channel 0 and select “Implicit Target” for the operation mode. This works for Explicit adapter as well. The Port Number and IP address sections are left alone, and we can then click “OK.” We are now ready to create a tag that will be accessible by an Explicit Client. We go to the Global/Direct Variable screen and insert a row. We can then create an array of elements 0 to 3 of data type “byte” and we will name it “EIP_SERVER_DATA.” This will be a global variable, and we will check the EIP/OPC UA box to make the array available for use with EtherNet/IP communications. Now that we have the array created, we can add this array to our Explicit Server by double-clicking on “EIP Block” in the project window. This opens the “LSPLC – EIP 03” window. We will set the channel to 0. As we have already set up channel 0 as an Implicit Target, it adds that to the operation mode. The only remaining field to be configured is the Local Tag field. If we double-click here, it will open a new pop-up window showing us all available variables that have had the EIP/OPC UA box checked. In our case, it is just the array we created. When we select it, the software adds it to the local tag location. Once we write this project to the PLC, we will be able to access this information from an Explicit Client. The primary difference between this data being accessed by an Implicit Scanner and an Explicit Client is in the data location. The Explicit Client will be able to access this data by using service code 14 or hex 0x0E “Get Attribute Single” for reading information, and service code 16 or hex 0x10 “Set Attribute Single” for writing. The class ID will be 4 for both, and the attribute ID will be 3. The Instance ID will depend on the index number in this EIP03 tab. For a Get message, the Instance ID will be 100 plus the index number, and for a Set message, the Instance will be 150 plus the index number. In our case, the get message Instance ID would be 100, and the set message would be 150 since we only have one value. If we had information in index 31 we wanted to access, it would be at instance 131 for the get, or 181 for the set. The data size for the client will correspond to the data type and data count columns. If our data type is 8-bit, and the data count is 4, we will have a get and set message size of 4 bytes. If, however, we are using a 16-bit type and a count of 8, for instance, the get and set messages will be 16 bytes. These numbers must be correct in the client, as the server will return an error if they don’t match. In this way, we can access up to 32 different variables or variable arrays for get and set data with the LS PLC acting as an Explicit Server.