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Multiple EmonTH

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(Bart Coddens) #1

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,
Bart


(Robert Wall) #2

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: https://wiki.openenergymonitor.org/index.php/EmonTH_V1.5#DIP_Switch_node_ID
and the programmer you need is this:
https://shop.openenergymonitor.com/programmer-usb-to-serial-uart/

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.


(Bill Thomson) #3

(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.


(Robert Wall) #4

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.


(Bill Thomson) #5

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


(Glyn Hudson) #6

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:


(Robert Wall) #7

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.