Corrupted data from RS485 Sensor Node

[Konrad Winiarski]

Hello. I'm using Arduino Pro Mini (atmega328) and checking one of basic examples (MotionSensorRS485). The gateway is connected via same RS485 converter. Unfortunately they do not communicate.
First I checked connection (direct TX-RX/RX-TX) connection - with failure. Then I took another USB/TTL converter to check what is on the output of softserial - and I found some kind of garbage data. It looks like wrong baudrate so I checked all "standard" speeds from 2400 up to 115200. (Configured to 9600).
Then I enabled DEBUG, enabled HWSERIAL and set to Serial. Both baudrates set to 9600. So I have now both, the communication frame and debug. See screenshot below.

When I disable DEBUG, only corrupted frame left:

The code:

//#define MY_DEBUG
//#define MY_DEBUG_LOCAL

// Enable RS485 transport layer
#define MY_RS485

// Define this to enables DE-pin management on defined pin
#define MY_RS485_DE_PIN 2

// Set RS485 baud rate to use
#define MY_BAUD_RATE 9600
#define MY_RS485_BAUD_RATE 9600 //19200 //57600 //38400 //9600
#define MY_RS485_SOH_COUNT 1
#define MY_RS485_HWSERIAL Serial
#define MY_SPLASH_SCREEN_DISABLED
//#define MY_PASSIVE_NODE
#define MY_NODE_ID 10

#include <MySensors.h>

uint32_t SLEEP_TIME = 3000;//+120000 // Sleep time between reports (in milliseconds)
#define DIGITAL_INPUT_SENSOR 3   // The digital input you attached your motion sensor.  (Only 2 and 3 generates interrupt!)
#define CHILD_ID 1   // Id of the sensor child

// Initialize motion message
MyMessage msg(CHILD_ID, V_TRIPPED);

void setup()
{
    pinMode(DIGITAL_INPUT_SENSOR, INPUT);      // sets the motion sensor digital pin as input
    
}

void presentation()
{
    // Send the sketch version information to the gateway and Controller
    sendSketchInfo("Motion Sensor", "1.0");

    // Register all sensors to gw (they will be created as child devices)
    present(CHILD_ID, S_MOTION);
}

void loop()
{
    // Read digital motion value
    bool tripped = digitalRead(DIGITAL_INPUT_SENSOR) == HIGH;

    Serial.println(tripped);
    send(msg.set(tripped?"1":"0"));  // Send tripped value to gw

    // Sleep until interrupt comes in on motion sensor. Send update every two minute.
    //sleep(digitalPinToInterrupt(DIGITAL_INPUT_SENSOR), CHANGE, SLEEP_TIME);
}

An Idea? Arduino board is not corrupted, any short sketch with SoftSerial library works fine. Haven't checked MySensors with SoftSerial though. MySensors version 2.3.2. Checked on Arduino IDE and VSC.
Cheers!

[cabat]

What about RS485 bus topology and connection to RS485 recievers on Arduino Pro Mini module?

[Konrad Winiarski]

Hi Cabat. Both checked. I wrote my own code to test it. I'm having my own working RS485 network at home already. I did it by myself and I'm pretty experienced in debugging ;). I want to switch to MySensors now due to more flexibility.
So to summarize:

• it is not a RS485 issue, tested,
• it is not a USB/TTL converter issue, tested,
• it is not an UART bitrate issue, not on the PC side at least,
• there is no difference if I use hardware or software serial - same content.

I have conserns about the Library. According to this page:
https://www.mysensors.org/download/serial_api_20
the typical frame sent by a node should be like this:
12;6;0;0;3;My Light\n
12;6;1;0;0;36.5\n
13;7;1;0;2;1\n

As you can see on picture in firs post, when I configured to use HWSerial for RS485 and DEBUG set ON, I shall expect both - Communication and Debug on the same line. Debug data is correct, but the frame is nothing like a text message - looks like the content is sent in HEX not ASCII.
I learned there is no encryption, so it is not an encrypted data I assume.

[karlheinz2000]

RS485 data is different to serial api. Serial api is only from gateway to controller.
Please check links in 1st post.
https://forum.mysensors.org/topic/1947/rs485-rs232-serial-transport-class-for-mysensors-org

[Konrad Winiarski]

Yes, I realized that last Sunday. I went through the code of library. I had to switch to another project for a week or so, then I come back to it. Thanks!