Zk-u485 Manual

[Gauthier Zitnik]

Afterlooking over their manual, it seems like the only difference is the RS485 physical link vs a direct connect using 5V TTL. The RS485 version has the benefit of longer wire runs without having to worry about noise. The RS485 version also draws a bit more power to power the RS485 electronics.

In this link there is a description of the ports/pins of the Pixhawk 2.4.8 that I use. But could someone more hardware experienced than me ( @iampete ) explain how I should connect the 4 wind meter wires with the Max3232 and Pixhawk pins?

The data lines of a RS485 are balanced pairs. When the voltage goes up on one line, the voltage goes down on the other. Using balanced pairs like this makes the signal much more immune to problems of noise. The transceiver takes the two signal lines and converts to signal which the flight controller can use. The datasheet calls the data out line Receiver Output (RO) (pin #1 on the chip).

The transceiver can both convert the balanced signal to a 3.3V signal and convert a 3.3V to the balanced pair. You likely will only need to receive RS485 signals so the flow control pin (DE) can be hardwired low.

Looking at the schematic on one the boards I designed which use this transceiver, I see I connected RE to ground and use the DE pin to control if the chip is in receive or transmit mode. If both these lines are tied low, the chip should be in receive mode all the time.

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