KepserverEX - Janitza S2 modbus communication problem

Greetings ​@David ,
 

Please try below steps to rectify the issue:

• Open your Kepware project and go to the Device properties for this connection.

• Look for the  Modbus TCP specific settings.

• Locate the Block Sizes settings (Holding Registers / Input Registers).

• By default, these are often set to 120 words. Drop this down drastically—try 32, 16, or even 8 words. 5. Why this helps: Smaller block sizes mean Kepware sends more frequent, smaller requests. If one request fails, it impacts fewer tags, and the Janitza device can process smaller chunks much faster.

Go to your Device Properties in Kepware and adjust the following under Timing:

• Request Timeout: Increase from the default (usually 1000ms) to 2000ms or 3000ms. Give the hardware a bit more breathing room to respond.

• Inter-Request Delay: Add a small delay of 10 to 20ms. This prevents Kepware from flooding the Janitza network card with back-to-back requests.

If the issue still persists then please enable the diagnostic and capture the logs and raise the ticket for the Kepware technical support team.

• Use OPC UA Diagnostics: In Kepware, right-click your Channel or Device and select Diagnostics. Enable it, then right-click again and select Diagnostic Viewer. This will show you the exact hex requests going out and coming back, allowing you to see if the device is explicitly rejecting certain blocks.

Regards,

Mohit