How to run two of the emonTx V3 on the same emonpi board

Hi, I have been trying to collect data from two emontx boards. It seems that it will alternate between the two. Is there a to set it up so I’m getting a live stream of both instead of alternating?

thanks

It sounds like the 2 emontx’s are both using the same node id. each device on the network needs to have it’s own unique id. The emonTx’s have a dip switch that select a node id of 9 or 10 (further choices involve a firmware edit).

https://wiki.openenergymonitor.org/index.php/EmonTx_V3.4#DIP_Switch_Config

you can just about make out the 2 dip switches in this pic, just under half way up on the lefthand side, they have a small piece of yellow tape/film that you need to remove first.

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Wow thank you so much for the quick. I was looking at the link you sent. So when dip switch for number 1 is off it is on node 8 but when it is on it is on node 7? do you need to change the settings anywhere else?

Ahh yes! I forgot later emonTx firmwares are 8 or 7 not 10 or 9, either way D8 (Dip SW1) which should be currently OFF should minus one from the current node id when switched ON, so if you currently have 2 x node 8’s, switching one will make it node 7, yes.

Thanks @pb66 You said that further chooses will need a firmware edit. Is there a way to have 4 emontx send data to a ras pi?

Thanks again @pb66

If the emonTx is running latest firmware (V2.6+) the RF node ID can be changed via serial config feature. No, firmware editing required.

If your emonTx is running older firmware, you can update to V2.6 using emonUpload:

man that sounds awesome. By using this I can make each emontx be on nodes 7, 8 , 9 ,10. So I would be able to run 4 different boards on one emonpi? @glyn.hudson

Correct :slight_smile:

However, you will need to make sure emonhub.conf on the emonPi has the correct node decoders entries to decode the RF received from each emonTx e.g here are node decoders for emonTx node 7 & 8. You will need to replicate these entries for 9 and 10.

[[7]]
   nodename = emontx4
   [[[rx]]]
      names = power1, power2, power3, power4, vrms, temp1, temp2, temp3, temp4, temp5, temp6, pulse
      datacodes = h,h,h,h,h,h,h,h,h,h,h,L
      scales = 1,1,1,1,0.01,0.1,0.1, 0.1,0.1,0.1,0.1,1
      units =W,W,W,W,V,C,C,C,C,C,C,p

[[8]]
    nodename = emontx3
    [[[rx]]]
       names = power1, power2, power3, power4, vrms, temp1, temp2, temp3, temp4, temp5, temp6, pulse
       datacodes = h,h,h,h,h,h,h,h,h,h,h,L
       scales = 1,1,1,1,0.01,0.1,0.1, 0.1,0.1,0.1,0.1,1
       units =W,W,W,W,V,C,C,C,C,C,C,p

There is aready a node docoder entry node for 9 & 10 present in the default emonhub config, this is for an older version of emonTx and can be overwritten. Here is the default emonhub config on the emonPi:

The config can be edited via the Admin > Config module in local Emoncms.

[[7]]
   nodename = emontx4
   [[[rx]]]
      names = power1, power2, power3, power4, vrms, temp1, temp2, temp3, temp4, temp5, temp6, pulse
      datacodes = h,h,h,h,h,h,h,h,h,h,h,L
      scales = 1,1,1,1,0.01,0.1,0.1, 0.1,0.1,0.1,0.1,1
      units =W,W,W,W,V,C,C,C,C,C,C,p

[[8]]
    nodename = emontx3
    [[[rx]]]
       names = power1, power2, power3, power4, vrms, temp1, temp2, temp3, temp4, temp5, temp6, pulse
       datacodes = h,h,h,h,h,h,h,h,h,h,h,L
       scales = 1,1,1,1,0.01,0.1,0.1, 0.1,0.1,0.1,0.1,1
       units =W,W,W,W,V,C,C,C,C,C,C,p

[[9]]
   nodename = emontx2
   [[[rx]]]
      names = power1, power2, power3, power4, vrms, temp1, temp2, temp3, temp4, temp5, temp6, pulse
      datacode = h
      scales = 1,1,1,1,0.01,0.1,0.1, 0.1,0.1,0.1,0.1,1
      units =W,W,W,W,V,C,C,C,C,C,C,p

[[10]]
    nodename = emontx1
    [[[rx]]]
       names = power1, power2, power3, power4, vrms, temp1, temp2, temp3, temp4, temp5, temp6, pulse
       datacode = h
       scales = 1,1,1,1,0.01,0.1,0.1, 0.1,0.1,0.1,0.1,1
       units =W,W,W,W,V,C,C,C,C,C,C,p

I think it might already be setup for four different devices trying to connect.

So can I use the dip switches on the emontx devices to hit each node?

You are right, emonhub is already set up for 4 emonTx’s, but the emonTx’s only have one node id dip switch, so there is only a choice of 2 node ids without hooking it up to a programmer. The second dip switch is for UK/US voltage selection.

Depending on when you bought the emonTx’s you may be able to just alter the node id via a serial connection, if not running the latest firmware, you may need to update the firmware to use a different node id on 2 of the emonTx’s.

Oh so dip 1 is node 7 or 8 and dip 2 is for uk us.

Got it about a three months ago

@glyn.hudson Are there any tutorials for how to flash using serial?

The readme on the emonTx 3 firmware page outlines the options available:

Man thank you so much. Just had a quick question, Does the range of the RF on the Emontx v3 decreases when running on the battery. Will running the emontx v3 on the usb will increase the rf range?

Thanks

No, range should be the same regardless of power supply.