Troubleshooting "Bytes Missing" in Modbus Poll: A Quick Fix Guide If you’ve been staring at a "Bytes Missing" error in Modbus Poll
Ensure 120-ohm terminating resistors are installed at both ends of the RS-485 network. Electrical Interference:
The Fix: In Modbus Poll, go to Connection → Connection Setup. Instead of selecting "Modbus TCP/IP," select Modbus RTU over TCP/IP. 2. Physical Layer and Wiring Issues modbus poll bytes missing error fixed
If you are using an RS485 adapter (e.g., Adam-4520, Waveshare):
Here’s an interesting, technically focused review of a Modbus Poll issue where a “bytes missing” error was fixed—written from the perspective of a power systems engineer or SCADA integrator who encountered the problem in a real-world deployment. Troubleshooting "Bytes Missing" in Modbus Poll: A Quick
The Issue
If the protocol settings are correct, the issue is likely physical. Step 1: Verify with a Loopback Test Disconnect
Disconnect the slave device and short the TX+ and RX- pins on your RS485 converter. Send a Modbus request. If you receive an echo, your serial port and cable are fine. If not, the issue is hardware-related.