LoPy + SP3485 + Modbus Lib Test. Register Read Error

[River]

@daniel It's possible to use the bus without control pin DE/RE (Will use automatic control)?

[Neuromystix]

@daniel Nice ;)

I'll try it then, because i will need to use the Sparkfun modules it in my current project.

Best regard.
Nelson Pinto

[daniel]

Hi everyone,

We are releasing tomorrow an improvement of the library together with a firmware release that will fix the timing issue with the control pin.

Cheers,
Daniel

[Neuromystix]

@mbriarg Same here. My setup use a Sparkfun RS485 breakout board, and even if i change the timeout_chars, i can't receive nothing (bytearray or no data errors).

With a chinese XY-017 module (which have automatic flow control) it works fine, always read without errors.

I assume that's something about the control pin, maybe the read/write timmings...

[mbriarg]

@daniel Thanks Daniel. Sorry for the delay. Your advice served me. I am managing to read registers but sporadically. Most of the time it responds that the slave does not send data or that the CRC is invalid. I still work and I consult you.

[daniel]

@mbriarg thanks for reporting this. Could you please try changing the timeout_chars value in this line: https://github.com/pycom/pycom-modbus/blob/master/uModbus/serial.py#L13

from 5 to something like 50? If it works, reduce it and keep testing until it stops working. Please let us know what's the minimum value that works with your setup. Thanks!