Hotel RS485 intelligent control panel failure

1, no communication signal, no response.

2. Data can be uploaded, but not downloaded.

3. The system prompt is disturbed during communication, or the communication indicator light flashes continuously when communication is not in progress.

4, sometimes can communicate, sometimes can't communicate, some instructions can pass, some instructions can't pass.

4. What are the debugging methods when something goes wrong?

Before debugging, first ensure that the equipment is correctly wired and the structure conforms to the specifications. According to the problems encountered, the following debugging methods can be adopted.

1, * * * method:

Connect the GND ground wires of all 485 devices with wires or shielded wires to avoid the power difference from affecting the communication between all devices.

2, the terminal resistance method:

A 120 ohm terminal resistor is connected in parallel with 485+ and 485- of the last 485 device to improve the communication quality.

3, the middle section disconnect method:

Check whether the equipment is overloaded, whether the communication distance is too long, and the influence of a certain equipment on the whole communication line.

4, line method:

As long as you pull a wire to the equipment, you can rule out whether the wire causes communication failure.

5. How to replace the converter:

Take several converters with you to rule out whether the quality of the converters will affect the communication quality.

6, notebook debugging method:

First of all, make sure that the laptop you carry with you is a normal communication device. Use it to communicate instead of the client computer. If it is normal, the serial port of the client computer may be damaged or damaged.