Convert dates | decoding an pplink (after a downlink) | BMeter IWM LR3/4

NadimFJTechLab · October 4, 2024, 7:26am

From this manual: https://www.bmeters.com/wp-content/uploads/2021/07/v1.0_IWM-LR3_LR4_UM_EN.pdf

I’ve done a downlink to get alarm data (3.11 in the manual, page 19), The downlink command is: 280000000104

The uplink i’ve received are as follows (several BMeters)

Header            01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
-----------------------------------------------------------------------------------------------------
28 01 00 00 1D 04 00 00 00 00 00 00 00 00 10 05 17 00 00 00 00 00 14 05 12 00 18 05 17 00 00 00 00 00
28 01 00 00 1D 04 00 00 00 00 00 00 00 00 18 09 18 00 00 00 00 00 05 09 18 00 00 00 00 00 00 00 00 00
28 01 00 00 1D 04 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 16 09 18 00 00 00 00 00 00 00 00 00
28 01 00 00 1D 04 00 00 00 10 00 00 00 00 00 00 00 00 00 00 00 00 1A 09 18 00 19 07 17 00 00 00 00 00
28 01 00 00 1D 04 00 00 00 12 00 00 00 00 04 05 12 00 00 00 00 00 07 09 18 00 02 06 17 00 00 00 00 00
28 01 00 00 1D 04 00 00 00 08 00 00 00 00 18 09 18 00 00 00 00 00 1C 09 18 00 00 00 00 00 00 00 00 00
28 01 00 00 1D 04 00 00 00 00 00 00 00 00 0F 05 17 00 00 00 00 00 1B 09 18 00 00 00 00 00 00 00 00 00
28 01 00 00 1D 04 00 00 00 02 00 00 00 00 0F 05 17 00 00 00 00 00 1D 07 18 00 00 00 00 00 00 00 00 00
28 01 00 00 1D 04 00 00 00 12 00 00 00 00 1A 02 18 00 00 00 00 00 17 07 18 00 03 04 18 00 00 00 00 00

Now when I’m trying to convert the dates, I’m not getting the correct ones. For example

00 00 00 12 00 00 00 00 04 05 12 00 00 00 00 00 07 09 18 00 02 06 17 00 00 00 00 00

00 00 00 12 (hex) = (bin) 00010010
00 00 00 00 (hex) = (dec) 0
04 05 12 00 (hex) = (dec) 67441152
00 00 00 00 (hex) = (dec) 0
07 09 18 00 (hex) = (dec) 118036480
02 06 17 00 (hex) = (dec) 33953536
00 00 00 00 (hex) = (dec) 0

Now when converting epoch to human-readable date, I’m now getting the correct dates (should be year 2024 at least).

Epoch 67441152 = Sunday, February 20, 1972 1:39:12 PM (GMT)
Epoch 118036480 = Friday, September 28, 1973 3:54:40 AM (GMT)
Epoch 33953536 = Thursday, January 28, 1971 11:32:16 PM (GMT)

What did I do wrong? Or the BMeter is sending wrong uplink? What are the solutions here?

Thanks,
Nadim

IoTThinks · October 5, 2024, 8:29am

In page 11, do you need to set the date and time for this node?

In this codec for uplink, it seems no datetime in the uplink in the decoder.

github.com

IoTThinks/lorawan-devices/blob/master/vendor/b-meters/iwmlr3.js

function decodeUplink(input) {
  //Decode an uplink payload
  var port = input.fPort;
  var data = {};

switch (input.fPort) {
  case 1:
    data.application = input.bytes[0];
    data.valueCounter = (input.bytes[4] << 24) + (input.bytes[3] << 16) + (input.bytes[2] << 8) + input.bytes[1];
    data.flowCounter = (input.bytes[8] << 24) + (input.bytes[7] << 16) + (input.bytes[6] << 8) + input.bytes[5];
    data.indexK = input.bytes[9];
    data.medium = input.bytes[10];
    //liters
    if (input.bytes[11] === 0x0D) {
      data.vif = input.bytes[11]*1;
    }
    //decaliters
    else if (input.bytes[11] === 0x0E){
      data.vif = input.bytes[11]*10;
    }

This file has been truncated. show original

NadimFJTechLab · October 11, 2024, 3:48am

No. This downlink (0x14) will be deprecated (according to the vendor), because it’s difficult to set the correct time (the downlink is not executed immediately after it is sent)

When you are installing this device on a mechanical meter, you set the date/time and also some other parameters (initial meter reading, k-index, etc) via a mobile app which uses NFC - so manually you set date/time.

system · January 9, 2025, 3:48am

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