Legal Removal Request

Post: Hi If the Raspberry Pis are communicating then that suggests it is a communication problem with the sensor. Looking through the information about the sensor on the page you linked, it looks like it should be able to communicate with the RS485 Pi so the first thing I would suggest is to make sure the connection between A and B pins and the ground on the sensor has a good connection with the RS485 Pi and check the GPIO header on the RS485 Pi to make sure there are no bridges or dry joints. We test each RS485 Pi before packaging so hopefully, there shouldn't be a fault with the board. Also, check that you fitted the supplied 120R terminator resistor as without that you could get reflections on the data bus that could stop it from working correctly. You may need to add a 120R resistor between the A and B pins at the sensor end of the cable as well. The datasheet for the sensor should say if this is already included inside the sensor or if it needs an external resistor when it is on the end of the data bus. If the hardware all looks good then it is most likely a software problem with the communication between the Raspberry Pi and the sensor. It may be worth contacting the sensor manufacturer to check if they have any tips on communicating with their hardware or if there are any software libraries available you could use.