RS485 Debug Process

Environment and Parameter Check

1. Confirm that the device power supply is normal.

2. Confirm whether the confirmation page data is consistent with the communication data.

3. Confirm that the RS485 function is enabled, the ID and Baud are defined correctly (parameters E04 E05).

4. Confirm that the advanced parameters are set correctly (parameters E15 E16 E17).

5. All unused wires are insulated, and there is no magnetic field interference in the surrounding area.

Hardware, Wiring, and Program of the Receiver Check

1. Confirm whether the RS485 command is used correctly.

2. Only one flowmeter is connected to the line, whether it can communicate normally.

3. Make sure the RS485 wiring is using the series connection method and not the star connection method.

4. In the case of multiple devices, is there any phenomenon that the power supply and ground wire of some devices are different, resulting in ground looping and potential fluctuation?

5. Does the line meet the requirements for twisted wire, thickness, series connection, and short fork?

6. For longer lines, do you use terminating resistors at both ends of the circuit?

7. For scenarios with large external interference, is a bias circuit used?

8. If there are multiple devices on the line, have you confirmed that the Baud of each device is the same and the ID is different?

9. Use an oscilloscope to see if the noise between the RS485 +/- lines is too high? (>200 mVpp generally considered too large)

10. Use a computer or a similar platform with high development flexibility to connect to a single flowmeter, first confirm that all communication settings and commands can communicate normally. Then modify the controller program.

Results and Actions

1. The RS485 output is normal, and the receiver equipment and programs are also normal. If the data is still abnormal, confirm other abnormal causes (pipe size, flow rate).

2. The main unit of this device may be damaged. If you have other units at hand, you can conduct a cross test to confirm that the receiving device, data processing program or line are all normal.

3. Please contact the original factory after recording the serial number of the fuselage, the wiring diagram (all flowmeter-related wiring) and the model brand of the receiving end.

4. If the line or environment cannot be improved, please allow the program to allow more re-communication attempts.

Users need to refer to the actual situation, detailed troubleshooting, please contact LORRIC.