OpenEnergyMonitor Community

emonTx connecting to arduino IDE using programmer

I have an emonTx and a USB to serial UART, which i have plugged into my laptop using a USB cable. I then go into Arduino IDE and select ‘serial monitor’ in the top right, but it says ‘board at null is not available’.

Does anybody know what i’m doing wrong. I’m trying to change node id so that i can have 3x emonTx on the same network.

Thank you

I have managed to get into the serial monitor now (i hadn’t loaded the drivers). Now need to work out when/how to enter +++

It will prompt you. You have 10 s before it times out and continues. Make sure you have “Both NL & CR” selected (bottom right).

There is a page in ‘Learn’ with the details.

Thanks Robert, it turned out that i had waited too long before entering +++. I restarted and did it straight away and manged to change the node id. Thanks for responding.

Another question if thats ok? Is it ok to connect the emonTx using Ethernet to the same network as the Emonbase and 2x other emonTx are on. The 3rd Tx is too far away for RF to work and wifi isn’t an option

Should i be able to see emnotx3cm17 in this list now that i have changed the node id to 17


Sorry i hadn’t update the config file in emoncms. I have done that now and its all working properly. Thanks for your help

Yes, but how are you going to connect it? – the RJ45 connector on your emonTx IS NOT ETHERNET. You’ll need a serial-Ethernet adapter connected where you plug in the programmer to the serial port.

The first move will be to prove the ISM band radio doesn’t work reliably - if it’s touch and go, it’s possible to turn up the power on the emonTx - but could bring different problems.

Or an Ethernet shield.

Not for an emonTx.

For some reason I was thinking emonTx Shield. :frowning_face:

Is a serial Ethernet adapter available in the shop? How do i turn up the power on the emonTx? It does have to travel through some pretty thick walls and is maybe about 30m away

I’m only getting readings of 300 from my CT clamps. Is there something i need to change?

All CT clamps are facing the same way, but i’m getting negative feeds?

Also does anybody know what ‘inactive’ means?

Inactive means “haven’t seen new data recently”. I’m not exactly sure what is considered “recently”, but it suggests you aren’t getting data.

On my Inputs and Feeds pages, that column includes a number of seconds, minutes or hours since each feed or input was updated, where yours says “Inactive”.

Looking at your screenshot, it looks like it is actually the temperature inputs that are showing 300. This would mean that no temperature sensor is present.

There’s a reference list here:

Thanks @Gwil that makes sense

Thanks @Greebo

Does anybody have any instructions to upload the firmware via serial to the emonTx? I don’t understand this GitHub - openenergymonitor/emonupload: Upload / update latest OpenEnergyMonitor firmware

Can I upload using Arduino IDE for example?