Enable "Log to File" in Modbus Poll, then examine the raw hex. The exact point where bytes go missing (beginning, middle, or end) tells you if it's a timing, hardware, or protocol issue.
Polling too fast (<50 ms) can overwhelm slow slaves, causing truncated responses. modbus poll bytes missing error fixed
If you are using a laptop with a USB-to-RS485 converter, the error might not be Modbus at all—it might be the USB driver. Windows USB drivers often introduce a high latency (delay) that breaks the strict timing required for Modbus RTU. Enable "Log to File" in Modbus Poll, then
Now go poll without fear. Your bytes will all arrive. 50 ms) can overwhelm slow slaves