485 Communication abnormality

HT001

485 Communication abnormality [Copy link]

I recently encountered a problem with 485 communication. I need help from all the experts. The situation is as follows: I use a Kunlun touch screen to read a 24V powered, 485 output temperature and humidity sensor. The two communicate through 485 signals. Recently, the temperature and humidity meter automatically restarts every 5 to 8 seconds. After restarting, the data on the touch screen is updated once. I replaced 3 temperature and humidity sensors and they are all like this. I replaced them with another brand of sensor and there is no problem. Has anyone encountered a similar situation? (The microcontroller of the temperature and humidity sensor is STM32F030F4P6)

chunyang

There are two reasons: power supply or communication. Check the power supply stability and manual of the thermometer to see if there are settings or functions that will cause the system to restart due to communication errors. You can also use a separate computer to monitor the 485 bus (read-only) to see if there is any connection between the bus status and the restart.

xiashuang

Analyze the communication protocol and communication delay