thanks for this will look into it also.
Then you have several ways to do this, including an RS485 MUX or switch.
I suggest you use the SP3075 RS485 IC, it's 3.3V has failsafe and you can multiplex them.
If you are making a PCB using ICs then it is not an issue.
I see XY problem here. Why don't you just post what you are looking for to approach starting from clean table? You might get good suggestions.
how far apart are the sensors and base station?
could the sensors communicate via WiFi, e.g, using ESP-NOW
Still need help?
oh yes. i was looking around for sample schematics for SP3075 and couldnāt find any. not even in the datasheet. is it just a bear bone chip on the board and nothing else? Iāll follow the AN-293-RS-232 and RS-485 PCB Layout guide.
thanks
No.
There is much more to designing an RS485 transceiver and digital circuits in general.
Have you done a PCB design before?
I have, but I doubt they are not as per standards. cant say i am good at them. further help would be very much appreciated.
My solution in the other topic was for UART with TX and RX connections. When you said you were going to use RS485, I did not consider the entire system and just focused on the master side.
Since the sensors can't switch between transmit and receive, it won't work with a half-duplex RS485 connection, you will need a full duplex connection and that will require 4 wires (plus power and ground) and different transceivers.
Or you can do as @Rintin suggested.
So you should uncheck this topic as being solved.
could you please elaborate a bit more on this? mainly on the network protocol part.
So I assume full duplex RS485 will not be considered?
With RS422 you run 2 differential lines. One for transmit and one for receive. I think this will result in a lot of wiring.
There are RS485 module with auto direction. However this requires that the sensor does not start a response while the request is still ongoing and the ESP has not switched to receiving. I don't know if the datasheet guarantees this.
You use twisted pair wiring to daisy chain all devices (just like modbus).
Now every device (sensor) has an address and listens on the network. They do not start an request.
The controller sends out requests with the address of one device. Only the device that is talked to sends a response. (just like... did I already say modbus?)
Is there a reason why you decided to use RS485?
cable length and interference tolerance
Well unless you want to put a microcontroller (that needs to be programmed) next to each Sensor, you will have to go full duplex using 4 wires.