Can't receive downlink

We successfully set up an end node that sending data to TTN, but right now I’m stuck with a downlink messages issue. We need to set up a working downlink to have the ability to control relays on our sensor from the Web-page.

What we are using:

Sensor:
Arduino Mega + Dragino Shield + sensors + relays
TX over OTAA works nice

Gateway:
Dragino lg308

Usually sensor in coverage of one more somebody else gateway
After sending the downlink request to TTN, I’ve got a message in the TTN console that the downlink is scheduled but that’s all, sensors not receiving any data, and the message looks like not going to the gateway.

I am trying to debug using integrated into lg308 gateway firmware LoRa logger, but the log is unclear for me
I think the TTN console gateway log would be helpful but for some reason in the TTN stack version log not working for some people (like me) all over the world as well as the gateway offline status issue, I found a TTN article about that.
I am attaching screenshots maybe they would be helpful:
image
image
Any advice or support on how I can debug downlink would be very appreciated

Attaching my end node code:

Code


static uint8_t mydata[] = “OTAA”;
static osjob_t sendjob;

// Schedule TX every this many seconds (might become longer due to duty
// cycle limitations).
const unsigned TX_INTERVAL = 60;

// Pin mapping for Dragino Lorashield
const lmic_pinmap lmic_pins = {
.nss = 10,
.rxtx = LMIC_UNUSED_PIN,
.rst = 9,
.dio = {2, 6, 7},
};

void onEvent (ev_t ev) {
Serial.print(os_getTime());
Serial.print(": ");
switch(ev) {
case EV_SCAN_TIMEOUT:
Serial.println(F(“EV_SCAN_TIMEOUT”));
break;
case EV_BEACON_FOUND:
Serial.println(F(“EV_BEACON_FOUND”));
break;
case EV_BEACON_MISSED:
Serial.println(F(“EV_BEACON_MISSED”));
break;
case EV_BEACON_TRACKED:
Serial.println(F(“EV_BEACON_TRACKED”));
break;
case EV_JOINING:
Serial.println(F(“EV_JOINING”));
break;
case EV_JOINED:
Serial.println(F(“EV_JOINED”));
{
u4_t netid = 0;
devaddr_t devaddr = 0;
u1_t nwkKey[16];
u1_t artKey[16];
LMIC_getSessionKeys(&netid, &devaddr, nwkKey, artKey);
Serial.print("netid: ");
Serial.println(netid, DEC);
Serial.print("devaddr: ");
Serial.println(devaddr, HEX);
Serial.print(“artKey: “);
for (int i=0; i<sizeof(artKey); ++i) {
Serial.print(artKey[i], HEX);
}
Serial.println(””);
Serial.print(“nwkKey: “);
for (int i=0; i<sizeof(nwkKey); ++i) {
Serial.print(nwkKey[i], HEX);
}
Serial.println(””);
}
Serial.println(F(“Successful OTAA Join…”));
// Disable link check validation (automatically enabled
// during join, but because slow data rates change max TX
// size, we don’t use it in this example.
LMIC_setLinkCheckMode(0);
break;
/*
|| This event is defined but not used in the code. No
|| point in wasting codespace on it.
||
|| case EV_RFU1:
|| Serial.println(F(“EV_RFU1”));
|| break;
/
case EV_JOIN_FAILED:
Serial.println(F(“EV_JOIN_FAILED”));
break;
case EV_REJOIN_FAILED:
Serial.println(F(“EV_REJOIN_FAILED”));
break;
break;
case EV_TXCOMPLETE:
Serial.println(F(“EV_TXCOMPLETE (includes waiting for RX windows)”));
if (LMIC.txrxFlags & TXRX_ACK)
Serial.println(F(“Received ack”));
if (LMIC.dataLen) {
Serial.print(F(“Received “));
Serial.print(LMIC.dataLen);
Serial.println(F(” bytes of payload”));
}
// Schedule next transmission
os_setTimedCallback(&sendjob, os_getTime()+sec2osticks(TX_INTERVAL), do_send);
break;
case EV_LOST_TSYNC:
Serial.println(F(“EV_LOST_TSYNC”));
break;
case EV_RESET:
Serial.println(F(“EV_RESET”));
break;
case EV_RXCOMPLETE:
// data received in ping slot
Serial.println(F(“EV_RXCOMPLETE”));
break;
case EV_LINK_DEAD:
Serial.println(F(“EV_LINK_DEAD”));
break;
case EV_LINK_ALIVE:
Serial.println(F(“EV_LINK_ALIVE”));
break;
/

|| This event is defined but not used in the code. No
|| point in wasting codespace on it.
||
|| case EV_SCAN_FOUND:
|| Serial.println(F(“EV_SCAN_FOUND”));
|| break;
*/
case EV_TXSTART:
Serial.println(F(“EV_TXSTART”));
break;
default:
Serial.print(F("Unknown event: "));
Serial.println((unsigned) ev);
break;
}
}

void do_send(osjob_t* j){
// Check if there is not a current TX/RX job running
if (LMIC.opmode & OP_TXRXPEND) {
Serial.println(F(“OP_TXRXPEND, not sending”));
} else {
// Prepare upstream data transmission at the next possible time.
LMIC_setTxData2(1, mydata, sizeof(mydata)-1, 0);
Serial.println(F(“Packet queued”));
Serial.print(F("Sending packet on frequency: "));
Serial.println(LMIC.freq);
}
// Next TX is scheduled after TX_COMPLETE event.
}

void setup() {
Serial.begin(115200);
Serial.println(F(“Starting”));

#ifdef VCC_ENABLE
// For Pinoccio Scout boards
pinMode(VCC_ENABLE, OUTPUT);
digitalWrite(VCC_ENABLE, HIGH);
delay(1000);
#endif

#if defined(CFG_au921)
Serial.println(F("Loading AU915/AU921 Configuration..."));
#endif

// LMIC init
os_init();
// Reset the MAC state. Session and pending data transfers will be discarded.
LMIC_reset();

LMIC_setDrTxpow(DR_SF7, 14);
LMIC_selectSubBand(1);
LMIC_setClockError(MAX_CLOCK_ERROR * 1 / 100);

// Start job (sending automatically starts OTAA too)
do_send(&sendjob);

}

void loop() {
os_runloop_once();
}

Thank you!

First, hopefully you understand that downlinks can only be sent in response to uplinks. Given latencies, that often means staged downlinks only send in response to the next uplink.

Examine the uplink reports; is your gateway the only one listed, or clearly the strongest RSSI? Is only the correct signal listed, or are there multiple receptions on various channels, some of which would be false bleedover from the node being too close to the gateway and overloading it?

It would also be good to capture gateway local logs through the entirely interval between and inclusive of two uplinks.