Emontx connecting to RPi 3

Both emonTx’s transmit on the same radio frequency, and both RFM69Pi’s listen on the same frequency.

What differentiates the two emonTx’s is they must have different NodeIDs. If you don’t do that, and I can’t see from that screenshot - and in any case we much prefer a copy & paste, the data will be mixed up and you won’t tell which is which.

What you need to do is configure your router to allocate a fixed IP address to each RPi, then in the emonhub.conf (not the log) for the RPi that you want to send the data to the other, put the receiving RPi’s IP address in here

    Type = EmonHubEmoncmsHTTPInterfacer
        pubchannels = ToRFM12,
        subchannels = ToEmonCMS,
        url = https://emoncms.org
        apikey = xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx 
        senddata = 0                    # Enable sending data to Emoncms.org
        sendstatus = 1                  # Enable sending WAN IP to Emoncms.org MyIP > https://emoncms.org/myip/list
        sendinterval= 60                # Bulk send interval to Emoncms.org in seconds

in the place where https://emoncms.org is, along with its APIkey on the next line, and senddata = 1 of course. You’ll get the receiving RPi’s APIKey from its Inputs Help page.

Before I go any further I have been messing about with some of the input readings and charts and had no idea how advanced this equipment is, I’ve spent thousands on fluke power quality analysers to get the same type of results that your equipment does for tens of pounds. I must apologize for making what I thought were helpful comments on other threads I will keep my nose out and just concentrate on getting my own house in order. I’ll get back to the matter in hand I can see I’ve got years of knowledge to catch up on.

I don’t think that is altogether necessary. True, I’d noticed the comments and my eyebrows raised a little. But cross-fertilisation of ideas is always welcome. It’s been a while since I had any direct involvement in power quality and stuff like that and I’m quite sure the ‘bells & whistles’ have advanced even though the underlying principles have remained much the same. And I’d caution about comparing the OEM kit against professional standard test gear with traceable accuracy.

Collectively, there’s an awful lot of knowledge and experience on this forum, if someone with the specialist knowledge doesn’t chip in, we can usually point you in the right direction.

Thanks for your understanding.

Is the APIKey the read only or the read and write.

I have changed the NodeID on one of the emontx so I have one on 15 and the other on 16

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It is the Read & Write that you want - sending the write APIkey back is the way the sender convinces the receiver that the data is legitimate.

I have two RPI on fixed IP address’s .120 and .179 hardwired on my network. I have two emonTX, one on node 15 the other on node 16. Both emontx show they are connected to .179 but I need one on .179 and the other on .120. I can’t seem to delete or move one of the emontx, such a basic question but one I can’t solve.

No, you can’t determine from the emonTx which RPi receives it - it’s just like a broadcast radio, once the message is broadcast, it’s out there for anyone to receive it.

Does RPi 120 see either or both the emonTx’s? If it doesn’t, it’s a radio problem - the signal isn’t being received.

Are all four (emonTx’s and RPi’s) all working on the standard frequency and Group No? (If you haven’t changed anything, they will be.)

The RPi 120 is not seeing either emontx. I’ve swapped the RFM69Pi between the two RPi. The 179 RPi still sees both emontx but 120 RPi still sees no input. The red light is on constantly on the RPi and the red light flashes on the RFM69P1 on both. I haven’t changed anything to do with frequency or group number.

This would seem to indicate that the RFM69Pi is receiving, so it sounds like a problem with the Pi itself. I’m not a Pi expert, so I’m hesitant to give any advice. Are both Pi’s new and running the same image? Is it possible to swap SD cards and see if the problem follow the card or stays with the Pi?

Ive swapped the SD card and the problem has followed the card. Both cards were bought at the same time pre loaded. I have 1 x RPi 3B and 1 x RPi 3B+ neither has been used for anything else.

I don’t know the difference between a 3B and a 3B+, nor importantly, whether it’s significant. There was a problem with a speed setting, I think it applied only to a Pi 2, and I thought that had been fixed - are the cards recently bought?

I’d suggest, if you have a computer with a card reader/writer, you could download a new image and write it to the ‘faulty’ card (using Balena Etcher is the easiest and safest - Using Etcher tool to flash emonSD image to SD card, or there’s this Alternative to Etcher to write images: USBImager).

If you don’t want to try that (or if it fails) then it could be a faulty card - email the shop with your order number and refer to this thread: supp[email protected]

Thanks for your help I will give it a try, big learning curve for me :woozy_face:

Can the RPi be programmed to switch a relay hat when the load exceeds 100A on a 230VAC supply. I’m looking at the situation where I need to do load shedding via a contactor but not sure if this is done through Emoncms programming or some other programming method and not being a programmer I’m a bit lost. There are priority devices that I can buy off the shelf but as I’m already looking at fitting the emontx to monitor the site energy I thought why not try and use that via the RPi.

There is this: WiFi MQTT Relay / Thermostat - Shop | OpenEnergyMonitor

I presume there’s something in the Resources/Wiki/Guide about setting it up, but as that’s not my area, I haven’t looked. Somebody else will need to help there - or with using the Pi Hat directly.

I’d suggest something like Home Assistant or Node-Red is a better solution in some, domestic, situations. EmonCMS can publish the data (current load for instance) on which a decision could be based. It partly depends on how quickly you need it to happen and the safety critical nature of the load shedding.

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Hi Brian
Sorry is Home Assistant or Node-Red some sort of programming. This is actually for a pub/restaurant that has ordered external parasols with 9kW of electric heating so I need to limit maximum demand as the place only has a single phase 100A supply. Switching speed isn’t critical as short term overload can be accommodated but if over 5 -10 mins I could start to reduce some of the load by operating contactors.
Thanks for your input.

TBH, I don’t think that is a very clever setup for a public facing organisation so I’m not prepared to offer any advice - sorry.

I’m sorry Brian you are quite correct I should not be asking such basic questions for a commercial implementation, I shall use off the shelf load curtailment until I have a better understanding of setting up something by my own means. I apologise if I have caused you any distress.

No not at all.

Good plan :slight_smile: