emonVS questions

When the emonVS was introduced, it provided voltage sensing and power for the emonTx4 via a 6 pin RJ11 connector at both ends, and power for the emonBase 433Mhz (RFM69SPI) via a USB-C connector

Looking at the photos of the emonPi2, it has an 8 pin RJ45 connector for voltage sensing and power; github and Docs confirm this.

The github changelog for the emonVS confirms that the voltage sensing and power connector was changed from a RJ11 to a RJ45 at V1.2, and the pinout matches the emonPi2. I’m guessing it was done to provide two wires for the +5V and two for the 0V power supply to the emonPi2.

According to github, the emonTx4 still has a RJ11 connector. So how does one connect an emonVS >=V1.2 with an 8 pin RJ45 to an emonTx4 with a 6 pin RJ11? And vice-versa, how does one connect an emonVS <V1.2 with an 6 pin RJ11 to an emonPi2 with a 8 pin RJ45?

It is possible to plug an emonTx4 6 pin RJ11 plug into the middle of an emonVS 8 pin RJ45 socket, to connect to pins 2 to 7. However the voltage sense and power pinouts don’t match.

Apologies to all if I have got something wrong, or missed the obvious!

Hello @rupert

This is correct, I realised we needed more current carrying capacity too late in the design with the RJ11 version. Hence the decision to switch over to RJ45 at the first opportunity with this new manufacturing run. Powering the EmonTx4 via RJ11 is fine as it’s a low power microcontroller. Powering a RaspberryPi is another matter. It’s unfortunate to have to make this change, but it’s for the better longer term.

For those ordering new hardware from the shop we will only have RJ45 emonPi2 units and RJ45 emonVs units going forward. The emonPi2 will replace the emonTx4. It’s worth noting that while it’s not the standard configuration, the emonPi2 measurement board has been designed in such a way that it can actually be used as a direct emonTx4 replacement for those interested in that same radio transmitter and separate base station functionality. So while we are discontinuing the emonTx4 this is only really in name rather than functionality as both the emonPi2 and emonTx4 measurement boards are essentially the same.

For those with an existing emonVs and emonTx4 wanting to add an emonPi2 to their system without buying a new emonVs, we would like to be able to support this. The best solution is probably an RJ11 splitter with one RJ11 going to the existing emonTx4 and another custom RJ11 to RJ45 cable that we would build up here that provides the voltage waveform to the emonPi2. This configuration likely replaces an existing emonBase with an emonPi2 i imagine? and so the USB-C power output cable on the existing emonVs could be plugged into the emonPi2 instead.

Hope that all makes sense?

Hi @TrystanLea

Thanks for the update - and yes, it does all make sense. Using an emonPi2 (without the Pi) as an emonTx4 replacement makes sense, and cuts down the different types of units OEM has to manufacture and hold in stock.

I’m a little sad to see the emonTx4 retiring so soon though!

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Yes I do like how compact the emonTx4 board is, but like you say cutting down on different types of units, allowing higher volume for one type of board should help longer term. Thanks for your comments on this!

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Losing out on the TX4 is a shame. I’ve been looking to expand my EmonTX3, adding additional CTs rather than replacing the existing solution.

A TX4 with a 6 port expansion + the legacy firmware would have been perfect. Putting an EmonPI2 in place of my TX brings a number of challenges (existing EmonBase is in my server rack, EmonPi2 only supports 6 CTs, incompatibility with my existing stock of EmonTH devices).

Frustratingly, there doesn’t seem to be a great fit for my current needs.

I think this is a huge mistake to discontinue EmonTX4

No one (sensible) can afford to buy two EmonPi2 if they have a requirement to monitor in two physical locations.

People who have invested in the ecosystem over the years are left without any way to expand capacity, including the add on board for EmonTX4 that was widthdraw less than 6 months after it was available. I see EmonVS mini is no longer in the shop either.

I really hope you bring back a sensible cost stand alone sensor like EmonTX4 was.

I really hope you consider in future a lifecycle and support products you discontinue for a number of years after they are withdrawn with the supporting parts, sensors and add on boards.

Ive added a longer comment about this here: What's happened to emonTx V4? - #4 by TrystanLea and will increase the priority level of making the Tx version of the emonPi2 board available as a clearer offering and better price point.

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