PLC SCADA Training:

3 Steps to Make Your Communication Work Like a Charm

Communication between PLC devices and SCADA is basically the main criteria for industrial automation. Therefore today we shall focus on simple configuration steps to achieve success communication.

Continued from previous training, Siemens PLC S7-1200 will be the PLC, while Ecava IGX will serve as the SCADA. Let’s start our training by opening the previous project. Note that different SCADA may present the configuration in different ways, but for Ecava IGX, it is simple and flexible.

PLC SCADA Communication is built when tags’ addresses from both sides matched. Once they are matched and recognized, then the polling can start and hence the read and write operation will work like a charm.

Step 1: Note the Different Groups/Blocks of PLC Tags

From the previous project, we have created IO tags for PLC communication. Note that in Ecava IGX Project Editor, we do not need to separate different types of IO tags into different tables. For instance, as shown in screenshot below, data block tags and PLC input/output tags can be included in the same IO tag table in IGX.

Step 2: Set Same Batch Number for Same Chunk of Data

In order to create lossless communication, we might need to look into the ‘Batch’ column. We shall go through the tags and understand how to make use of batches. For Ecava IGX, ‘Batch’ is presented in number format, in which the numbering indicates if a chunk of data for one device shall be read/write together if they are contiguous in data address arrangement. Therefore, in short words, if there is a group of tags with contiguous address and same data type, we will set them with same batch number (meaning they will be polled as same batch). Otherwise, we will just put them into different batches by setting different batch number.

Ecava IGX PLC SCADA communication set same batch number for same group tags

From the screenshot above, noticed that the first 9 tags are not contiguous as well as not from the same data type. Thus, they are being set with different Batch numbers (as shown in the screenshot, Batch numbers are different from 1 to 9). While for the following tags (i.e. ‘DB_Tag_10’ to ‘DB_Tag_14’), they are having same data types and contiguous in address. Therefore they will be put and polled as the same batch/group, and hence having set the same Batch number (i.e. 10) in Project Editor.

Next, we move on to the PLC input and output tags. In this project, we have created each of the tags in different data type and hence non-continuous address assignment. Similarly as mentioned before, each of these tags will be set in different batch because they will be polled in different groups.

Step 3: Identify and Set Input Tag (Yes or No)

These steps are indeed a wise approach to configure your device tags to achieve lossless communication. In fact, other than using Batch to group the tags, we can also make use of ‘Input Tag’ setting to optimize your system by bypassing unnecessary logic scanning for input or output tag determination.

Ecava IGX PLC SCADA communication identify input PLC tag

For PLC input tags, simply select and set to ‘True’ from the dropdown list. Else, just set it to ‘False’, as shown in screenshot above. Basically, the best practice is to avoid any unnecessary workload of the system, by narrow down the criteria for searching and filtering as best as possible.


Download Ecava IGX today and implement these best practices to optimize your PLC / SCADA communication.


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