EISv5 Simple Config - Changing Connection Parameters
- Andreas Luft
This guide shows how to change IO data sizes of one connection to the own needs.
Using basic configuration packet set, the determination of input and output data sizes is a part of it.
To avoid confusion, we use the following terminology:
Originator-To-Target (O→T) data
Target-To-Originator (T→O) data
There are also consuming and producing assemblies which contain IO data in the target device. Consuming assembly contains O→T data, which is the input data from our target device's perspective, producing assembly contains T→O data, which is respectively device's output data.
Stack Configuration
The configuration part is located in AppEIS_DemoApplicationFunctions.c:
In the basic configuration, a definition of only two assemblies is possible, in example:
O→T instance 100 (0x64)
T→O instance 101 (0x65)
Basic configuration set provides 3 possible connections, Exclusive Owner, Input Only and Listen Only connections.
Apart from Input/Listen Only connections, Exclusive Owner connection, as the name indicates, is exclusive and can be established only once.
Explanation: Since only one consumer assembly is available, only one originator can provide data to target's consumer assembly.
Connection path to Exclusive Owner connection looks this way:
200424012C642C65
The first 2C is pointing to the consuming assembly instance 0x64 and the second to producing assembly instance 0x65.
With Hilscher Ethernet/IP Tool, an Exclusive Owner connection to a Target Node IPv4 address can be established by setting the data sizes and connection path as follows:
(choose the proper Ethernet adapter under Preferences)
The process data structure is exemplary:
 and can be modified, e.g., by adding two additional bytes to input and output data:
Adapting the O→T and T→O sizes to the new configuration, a connection with 8 input-, respectively 12 output bytes can be established:
EDS File Modification
EtherNet/IP PLCs use Electronic Data Sheets (EDS) which describe the features of the device. Furthermore, the connection data sizes are a part of the EDS file content.
A simple way to create and modify an EDS file is by using the EZ-EDS tool. You can find the tool under the following website:
https://www.odva.org/subscriptions-services/software/ez-eds-download/
After opening the EDS with EZ-EDS, the content of the file will be more readable.
In the Connection Manager section, all the connections are defined. The Exclusive Owner connection has the O→T size of <Size of O→T format>, that means, the size is calculated automatically by the given format of Assembly Instance 100 (0x64).
The format is defined by assembly reference Assem100.
The assembly Assem100 (0x64) consists of 6 bytes (3 words).
The assembly Assem101 (0x64) consists of 10 bytes (5 words).
We could just extend Assem100 - Consuming Assembly and Assem101 - Producing Assembly by simply adding of existing Param2 - Consumed Data (one word), respectively Param1 - Produced Data to match the assembly sizes, and we would be done.
The more completely procedure is to add the additional words with proper names to benefit from parameter definitions which are shown in PLC software. At first, add a new parameter as shown below:
Name it meaningful, for produced data check Read Only Parameter, choose UINT for 16bit word as defined in host application:
Add this new parameter to producing assembly:
Create also consumed data parameter (non-read only) and add it to consuming assembly:
Finally, set the proper Size of the Data Block (in bytes) in both assemblies …
… and save the file:
After importing the EDS in PLC configuration software, like Communication Studio, the new parameter will be shown.
