Time out error and checksum error in modbus poll and modbus scan

Hi i have tried to capture the data from smart power meter using RS485 converter and modbus poll software

initially i got the values which were recorder after sometime i am getting checksum and time out error

I have verified parity, baud rate, bit rate all are correctly mentioned, disconnected wiring and connected again but same is showing with RS485 convertor

i am unable to sort out the error can anyone please help me on this

Please help me i am stuck on the project


Timeout means that the Master fails to gets a reply from the slave. Some reasons for that are

1. Cheap USB-RS-485 converters are known to fail with the tight timing restrictions of Modbus RTU. Those with FTDI chipsets have proven reliable. The checksum error makes me suspicious of the converter.

2. A/B +/- driver lines are backwards. Have you tried swapping the driver lines on one end? (There is no consistent agreement on the labeling of driver lines)

3. Are you sure the slave is configured as slave #1? Any slave other than #1 will not answer.

4. The USB/485 converters install on virtual COM port. Check Device Manager > Ports to confirm that COM port that USB/485 converter installs on. That COM port has to match the setting in Modbus Poll's connection setup.

5. Cycle power on the slave device if you have changes any serial setting or slave address for the change to be recognized.