Reconnecting with Kontar

Solution of communication issues between Weintek and Kontar PLC





At the beginning of 2025, several facilities with automation assembled on Kontar PLC (MZTA) and Weintek operator panels came for service.
The shields were assembled according to approximately the same principle:
-PLC master in the RS-485 network with additional PLCs and input/output modules (slave);
- The panel is connected to the PLC via Ethernet, via the Weblinker submodule.
During the maintenance process, we encountered several problems that needed to be solved. Three types of problems were identified, the symptoms of which were very similar in appearance - the elements of the mnemonic scheme disappeared when switching from screen to screen. The panel variables that were associated with the variables in the PLC (pumps, boilers, pressure and temperature values) were not displayed for a long time.

1. The problem of communication of a part of the Weintek project with a PLC that does not exist on communication.

The shield was in the boiler room. The boiler room is block-modular, such apartment buildings in small towns are heated.
Having connected to the PLC via the USB Weblinker connector and via the Console (MZTA), I found out what network settings the PLC has (I attached the photo for example).



The network settings of the operator panel are indicated on the same window. After connecting to the Ethernet network (PLC-PANEL-Router), I used the standard Weintek – EasyDiagnoser tool, which is included in the software package when installing EasyBuilder Pro.
How to use this application, you can find out from the video link below:
https://www.rusavtomatika.com/video/ispolzovanie-easywatch-i-easydiagnoser-weintek-easybuilder-pro-n...
EasyDiagnoser diagnostics showed that several variables are queried with an error, as indicated by the red bar in the line as in the figure below (the figure is attached for an example).



After studying the names of the variables, we came to the conclusion that they all belong to the same PLC (shield of one of the boilers). It turned out that the boiler was repaired and de-energized, which is why the operator panel could not interrogate this PLC. This information was initially missing.

2. Weblinker module malfunction problem

A shield in the center.
According to external symptoms (there is no display of elements on the mnemonic circuit), the situation looked very similar. Having connected to the PLC via the USB Weblinker connector and the Console software (MZTA), we found out what network settings are set for the PLC. Next, in order to use the EasyDiagnoser tool, we connected to the router and realized that there was no survey (data is not coming). We tried to connect directly to the PLC via the Weblinker Ethernet connector, ping it via the command line, but we did not achieve the result. It's good that there was a spare (for tests) PLC Kontar. We pulled the Weblinker module out of it, installed it on the PLC in the shield and everything worked. Moreover, it was not clear from the indication that the module was defective.
As a result, it was found that the problem was in the Weblinker module, namely, the part of it that was responsible for the Ethernet channel was faulty.



3. The problem of password mismatch

The solution of this situation took the most time.
The object is a boiler room, five boilers with shields and a general-purpose shield.
The problem was in the hotel-wide shield. The panel project was organized in such a way that after three minutes the screen with the mnemonic scheme switched to the screen with the logo of the organization that created this project (my advice is not to do this).
After connecting with the EasyDiagnoser tool, it turned out that when polling variables, the panel was sometimes polled with errors, but this did not affect the display on the mnemonic. However, when switching to the screen with the logo, the survey stopped and resumed only after returning to the main mnemonic.
At the same time (an important moment), waiting for the survey to resume could reach up to 60 seconds, all this time nothing was displayed on the mnemonic except static pictures.
In one of the TG chats, a colleague suggested that the problem may be related to the use of abnormal images on the mnemonic circuit, which is why the "picture" is immersed for a long time. Perhaps this influenced, but it never came to changing the mnemonic scheme. We decided to go the other way - to remove the transition to the window with the logo from the project and leave the window with the mnemonic circuit constantly in operation.
We unloaded the project using a flash drive, decompiled the unloaded project, made changes, and then dancing with a tambourine began. After uploading the project back to the panel, they saw the message "Device No Response" and there were no elements on the mnemonic.
We omit the description of the manipulations carried out that day, but the result was the same. Despondency and longing. Fortunately, the project was unloaded using a flash drive, after loading the old project back from the flash drive, the panel "came to life".
It became clear that the problem lies precisely in the EasyBuilder Pro software and when decompelling the project, the program made some changes invisible to the eye, which led to the termination of the panel with the PLC.


What was the problem in the end:
In the properties of the Weblinker network settings (MZTA), the password "12345678" is set by default (circled in red in the figure).





When decompiling a project in EasyBuilder Pro, this password is truncated to two characters, i.e. the password is "12" (circled in red in the figure). 



Of course, this password was visible in the settings, but there was no description of what it was for anywhere. After setting the appropriate password (12345678) and uploading the project with changes to the operator panel, the polling problem was fixed.










#MZTA, #Kontar, #Weintek