Multiple EmonTH

Hi All,

I bought 5 EmonTh devices together with the EmonBase.
All the devices show up as emonth5 , how can I identify the individual ones ?

Best Regards,

Unfortunately, you have a problem.

Inside the emonTH, you will see two DIP switches. (They might be covered with an orange film.) Those switches allow you to set up 4 units with individual NodeID’s, but unfortunately you need to re-program the EEPROM or edit and reload the sketch to change the number range of the switches for unit number 5 (or more!), and you need a programmer to be able to do that.
The instructions for the DIP switches are here: EmonTH V1.5 - OpenEnergyMonitor Wiki
and the programmer you need is this:
Programmer - USB to serial UART - Shop | OpenEnergyMonitor

Node ID = 19 is reported as emonth1, Node ID = 26 is reported as emonth8, so all your emonTHs are Node ID = 23, the default.

I’m a little surprised that the shop did not notice and ask you, because they would have set up the units for you, had you asked.

(After the address issue is resolved…)

With 5 devices, the probability is quite low, but there is a chance that some data might not get
passed upstream due to collisions during data packet transmission. It’s not likely to happen very often,
but I wouldn’t rule it out altogether.

True, but at the moment, all 5 of Bart’s emonTHs are all feeding into the same input on his emonBase, so that’s 100% collisions. :cry:

The emonTH reports approximately every minute, and the transmission lasts only about 3 ms (from memory), so the probability is indeed low, but finite.
But worse, if all 5 run at almost exactly the same speed, they could block each other for quite a long time.

I mentioned it so he’d know what was happening once he gets the addressing issue resolved.

1 Like

Re-compiling the code is not required the 5th node ID can be changed using serial config, this does require a USB to UART cable:

I didn’t say that recompilation is required to change the EEPROM setting, but a programmer is still required, whether you edit and recompile the sketch or configure the EEPROM using the serial port.