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The data is transported between the emonTX and emonBase in a structure called payloadTX. You need the same payloadTX in both the emonTx and emonBase. You fill it with the data in emonTx, then in the emonBase you need to extract the data and write it into a string to send to your database.

Looking at emonTx_CT123_Voltage.ino, payloadTX is defined:

typedef struct { int power1, power2, power3, Vrms; } PayloadTX;         // neat way of packaging data for RF comms
PayloadTX emontx;

and filled:

emontx.power1 = ct1.realPower;
.... [etc]

In the emonBase, looking for example at NanodeRF_Power_RTCrelay_GLCDtemp.ino, we have the same definition, the data is extracted and written as ASCII characters into str with:

          str.print(",power1:");        str.print(emontx.power1);          // Add power reading
          str.print(",power2:");        str.print(emontx.power2);          // Add power reading
          str.print(",power3:");        str.print(emontx.power3);          // Add power reading
          str.print(",voltage:");         str.print(emontx.voltage);          // Add emontx battery voltage reading

If you don't have exactly the same definition of payloadTX at either end, your data will be corrupted. So all you need to do is edit your (working) emonBase sketch to make payloadTX the same as in your emonTx, and write the values into str following the format above. The names that introduce the data "power1:" etc. are the names you used in your database.

Hello Roger, The sketch emonTx_CT123 is CT only measurement while emontx_temperature_power requires a voltage measurement with an AC-AC voltage adapter.

It might be worth looking at this page: http://openenergymonitor.org/emon/emontx/firmware/writing-code-for-the-emontx it goes through how to build up the emontx code from scratch and might help with understanding the full code.

If you dont have a AC-AC voltage adapter for voltage measurement, you will need to use the ct1.calcIrms(1480); rather than the ct1.calcVI(20,2000); function. 

Thanks for the pointers.  Will go and get my hands dirty with the code.  Last time i did any sort of programming, I was at college (and that was over 15 years ago).

After several evenings randomly typing things in on the keyboard :), i now have a working set of data readings in my serial monitor, as below:-

Open Energy Monitor - EmonTx
797.07 watts
3.32 amps
3236v battery
19.37C
 

However despite my best attempts i still cannot get a working sketch, that sends the data via a "Payload".  when i attempt to send the data the serial monitor does not show any of the readings, but if i comment out the send_rf_data(); line then i get back the data readings in the serial monitor.  Am i right in thinking that something in the rf_send_data loop is falling over, and thus stopping progressing onto my print_to_serial loop?  Could it be that the payload line of the code is setting up several variables as int, and most of my data readings are double?

If it helps i have uploaded my current working sketch at

https://www.sugarsync.com/pf/D7395264_875_674117976

Thanks

Roger

I don't think you sent the correct sketch! I can't see where you are sending the RF data in that one.

Good point about the sketch....

Try this one https://www.sugarsync.com/pf/D7395264_875_685793002

Two problems:

1. You were not starting the watchdog,
2. You hadn't initialised the RF12B module.

You need to add

  rf12_initialize(nodeID,freq,networkGroup);                       // Initialise the RF Module
  rf12_sleep(RF12_SLEEP);                                                  // and put it to sleep
 
  if (UNO) wdt_enable(WDTO_8S);                                       // Enable anti crash (restart) watchdog if UNO bootloader is selected. Watchdog does not work with duemilanove bootloader

at the end of setup( ).

It seems to work then for me (though the data the other end is rubbish because I don't have the same payload - but I understand that. I don't have temperature sensors either, so I cannot be absolutely certain those are working, but I get -127 out which looks believable for no sensor.

Come back if you need any more help.

 Hi all

After a few days away from my project for the bank holiday.  I am now back and realising that i should have taken more interest in my coding lessons at college.

I have now made some changes to the sketches on my emontx and emonbase.

I am now able to log some real data to emoncms.org. But the problem that i am having is that i am not logging the power value.  This is showing up fine in my emontx serial monitor.  But it is not showing up in my emonbase serial monitor or the actual emoncms feed.

Some hints or pointers in the right direction would be great. :)

Here are my emoncms feeds

http://emoncms.org/rogerrally&id=1316

http://emoncms.org/rogerrally&id=1317

 It seems to me that you aren't actually calculating the Power. In the emonTx, in loop( ), you have:

void loop()
{
emontx.current = ct1.calcIrms(1480); // Calculate RMS current (1480: no. of samples)
emontx.power = emontx.power * 240;

Now I can't see where  emontx.power  gets assigned a value in the first place - before it is multiplied by 240, that is. I think what was intended on the last line there, is:

  emontx.power = emontx.current * 240; 

You got the current in the line above. Multiplying by voltage should give you power. This assumes a fixed voltage of 240 V (and unity power factor!).  If you know your average supply voltage, you should substitute that instead. Alternatively, you could tweak that number so that the energy readings over a period correspond to those recorded by your tariff meter. I can't immediately spot anything else wrong, so hopefully with that change it should work.

 Hi Robert

Again you have come to my aid.  Again you were correct as to what the fix was.

Many thanks for your assistance, if we ever meet i owe you a beer or 2 (or a donation to a charity of your choice).