M-Bus Meter Reader, Sontex 531 Heat Meter

Frans · 12 March 2019 22:07

learn every day

Frans · 12 March 2019 22:53

I set two Mbus reader files in compare. one whit runing HP and one whit standing HP

schoult it now not be so that the values gives the different types?

TrystanLea · 13 March 2019 10:38

Great thanks @Frans, you could try this as a starting point:

#ifdef KAMSTRUP_302
  Serial.print(F(",KSVolumeFlow:")); 
  Serial.print(decode_4byte_bin(55),1);
  Serial.print(F(",KSHeatAv:")); 
  Serial.print(decode_4byte_bin(61),1);
  Serial.print(F(",KSflowT:")); 
  Serial.print(decode_2byte_bin(73)*0.01,2);
  Serial.print(F(",KSreturnT:"));
  Serial.print(decode_2byte_bin(77)*0.01,2);
#endif

Do you see how KSflowT starts at byte 73 in your print out above? there are two DATA bytes 73 & 74 same for KSreturnT 77 & 78…

Its not entirely clear what the kWh heat and non-averaged heat is…

Sometimes there are multiple pages of data that you can access, so it gets more complicated Im afraid…

Frans · 13 March 2019 12:17

Many thanks Trystan,

I have 2 print now. . first 2 request data fror Mbus reader, one running an stop HP.
i set in the data on the display from the Kamstrup.

then a print whit the inputs from running and stopt HP

I mus confess that i have no idee how to read the figures from the Mbus reader.
is the line number for every byte?MBUS files compare 13-3.pdf (43.5 KB)
MBUS inputs.pdf (35.2 KB)

TrystanLea · 13 March 2019 12:25

Great, the temperatures look good! What would you expect your flow rate to be in Litres per minute or m3 per hour?

byte id, value decimal, value hex, description
72       89             59         VIF Flow Temp 0.01C
73       156            9C         DATA
74       16             10         DATA

the byte id is a counter starting from 0 at the start of the message.

Frans · 13 March 2019 12:41

KS display dates
t1 = 39,35
t2 = 35,41
delta t = 4,23
l/h = 4278 flow heatside
kw = 20,5 energy given heatside
e1 = 3692,1 kwh ? i ges its total

TrystanLea · 13 March 2019 13:32

Thanks Frans, could you copy and paste result of MBUS inputs for the same instance as your readings from the display? Is KSVolumeFlow the same as l/h? I assume temperatures agree?

Frans · 13 March 2019 14:09

Trystan, the file MBUS files compare I send eelier this morning are from today.

One is whit running Heat pump and one is after the HP was stopped.

What’s wondering me is that there is no different. The flow of 4278 l/h must have given a different value or not in compare whit 0 l/h ? Or could be that there is need a longer time between the reading and the MBus ?

the temperatures are OK

i go down to the celler and check again.

Frans · 13 March 2019 14:13

volumeflow on inputlist is now 7359 and on KS display 4283 l/h

Frans · 13 March 2019 14:22

now the HP stoptand the input KSvolflow stays on 7857 while the flow now is 0

TrystanLea · 13 March 2019 20:37

hmm, not sure what KSvolflow is reading. Could you copy a graph, is there an accumulating trend or is it more a square wave steppy type shape? as the heatpump turns on/off?

Frans · 14 March 2019 21:15

Hello Trystan,
Now I get some understanding I did some test.
Listing data from Mbus serial reading I select the data who chancing.
Then I make the them serial printing by next changes to test.

mbus reader data 2.pdf (43.1 KB)

#ifdef KAMSTRUP_302
Serial.print(F(",KSVolumeFlow:"));
Serial.print(decode_4byte_bin(55),1);
Serial.print(F(",KSHeatAv:"));
Serial.print(decode_4byte_bin(61),1);
Serial.print(F(",KSflowT:"));
Serial.print(decode_2byte_bin(73)*0.01,2);
Serial.print(F(",KSreturnT:"));
Serial.print(decode_2byte_bin(77)*0.01,2);
Serial.print(F(",KSkWh_fo15:"));
Serial.print(decode_4byte_bin(15));
Serial.print(F(",KSdeltaT_fo27:"));
Serial.print(decode_4byte_bin(27));
Serial.print(F(",KSheat42:"));
Serial.print(decode_4byte_bin(42));
Serial.print(F(",KSflowrate_fo49:"));
Serial.print(decode_4byte_bin(49));
Serial.print(F(",KSkWh_fo55:"));
Serial.print(decode_4byte_bin(55));
Serial.print(F(",KSdeltaT_fo81:"));
Serial.print(decode_4byte_bin(81));
Serial.print(F(",KSheat85:"));
Serial.print(decode_4byte_bin(85));
Serial.print(F(",KSflowrate_fo97:"));
Serial.print(decode_4byte_bin(97));
Serial.print(F(",KSdeltaT_fo98:"));
Serial.print(decode_4byte_bin(98));
Serial.print(F(",KSheat:203"));
Serial.print(decode_4byte_bin(203));

#endif

Loading the script and cheking a time whit out, start, running and stop off the heatpump.

I listed the serial monitor in a exel file and put the results in a print as I send hierby.

mbus reader seriele monitor 2.pdf (45.1 KB)

Frans · 28 March 2019 09:52

Hello,

After some testing I became the Mbus reading looking pretty good.

But by further testing I became no good figures for the electric consumption from the 3 CT.

Therefore I installed a kWh meter (IME Conto D4-pd) whit a pulse-output.

I connected this to the board but I become no results from Elster meter reading.

The R8 and C1 are mounted and I can measure that the input D3 is switching when I manual make pulses on X7.

Whit all these issues the Mbus give now no response anymore. I measured 24 volts on the Mbus connection, is that correct.

Now I have 3 questions.

- Any suggestions why the pulsmeter dos not react.
- Can I make a serial print for the CT meters for volt and current
- Is the 24 V on the Mbus connection correct.

thedawnbefore · 24 May 2022 12:54

Greetings all,

Given the progress above, i’ve had a Sontex 531 fitted as part of our Heat Pump install and having some difficulty getting any signs of MBUS life from it. The unit itself is working perfectly alongside it’s Superstatic 440 flow meter. I was careful to buy the MBUS variant (albeit second hand) and wondered if anyone could confirm.- either from the board or the label on front - that this definitely has an MBUS module onboard?

The emonpi is reading the SDM120 fine over MBUS using OEMs USB module and I’m just trying to isolate the issue by checking it’s nothing as daft as not having MBUS compatibility. I’ve not had any success in asking Sontex directly…

Many thanks
Ben

TrystanLea · 24 May 2022 13:22

Hello @thedawnbefore looks fine, have you set the MBUS address? There’s a bit on how to do this here: Reading from multiple MBUS meters with the EmonHub MBUS interfacer - #5 by TrystanLea you should also be able to read what the address is on the Sontex LCD itself.

TrystanLea · 24 May 2022 13:23

I assume the blank LCD on the Sontex is just the disconnected head unit?

thedawnbefore · 25 May 2022 20:41

Thanks Trystan, that’s helpful - I hadn’t seen your address script which I’ll definitely give a go. I’ve since sent the meter off for glycol calibration (which is why the head unit is blank( so will try this as soon as it’s back. Thanks.

Brain1000 · 27 July 2022 11:08

Hi Ben, did you manage to get your m-bus interface working.
Just for info the Sontex 531 menu system shows if the m-bus option is fitted. It is option 7 (configuration) - Options.
I am having the same problem of no data using the USB to m-bus adapter on the EmonPi. Unfortunately I get “no reply received” using Trystan’s py scripts.
Brian

TrystanLea · 1 August 2022 11:05

Hello Brian, is your Sontex 531 powered with AC or battery? Is the baud rate and address in the emonhub config the same as that listed on the display?

Brain1000 · 1 August 2022 18:33

Hi Trystan,
The 531 is AC mains powered. The baud rate and address on the display are the same as entered in the emonhub. I have also used your py script to check the meter is responding on the correct address - this also is unsuccessful.
I have also tried using a different cable to connect the meter to the USB interface.
Any ideas would be gratefully received.
Brian