I am looking to purchase a 3 phase iammeter but only if I can get power values locally every 1 second as I need to monitor real time power usage. I have seen in other threads the current firmware updates every 6 seconds - this is no help as 6 seconds is too slow. 

There are a few ways you could implement 1 second power updates that should have minimal impact and minimal load on the iammeter - you could make the iammeter output locally a simple json formatted or mqtt datastream at a url similar to http://iammeter.ip/json/stream  or http://iammeter/mqtt/stream - we could then either subscribe to that mqtt steam or use a python (or similar) script read the stream use it for our purposes. On Github I have written a python script that takes a json stream and converts it to a mqtt stream - it would be simple to modify this if the iammeter is able to serve a json stream. https://github.com/vk2him/Enphase-Envoy-mqtt-json

In fact, we have provided such a local API that you can get the json data by HTTP get locally.

https://www.iammeter.com/docs/integrate-with-PVOutput

But no matter the local API or publishing data to a third-party server, the minimum data refresh interval is limited to 6 seconds.
we limit the 6 seconds not because we do not know how to do more faster but for some other concern(not corresponding to technology).
You can think that we still do not want to release the high-speed firmware version now.
When we want to support the 1sec sampling in the future, we will release a firmware and publish it in the top thread of our forum.

Thanks - to help me decide if I should buy or not, can you share with me the concerns you have (not relating to technology) that you have about faster than 6 second updates. 

All I can think of is that you may have plans to want to charge a subscription fee for faster access? I hope that isn't correct - any additional information will help.

Thanks

Shorter the upload interval may cause more service cost of IAMMETER, this part of the service cost has not been included in our products price now. if we provide the 1sec service in IAMMETER-cloud(just display and subscribe service, not store the data ), it will increase the price of the product.

But we do not think the 1sec sample interval is necessary for most of our customers. It is not reasonable to increase the product's price just to meet the requirements of a few parts of customers.

There will be some solutions if we want to solve this problem in the future.
1 do some logic in firmware. If you want to upload data in 1 secs interval, you can only use your own server. If you use IAMMETER mqtt service, the minimum interval must be 6 secs.
2 open the authority of high-speed uploading in IAMMETER-mqtt but charge the extra service fee to the customer who requires such service.

But no matter which method to be used, there are a lot of works that need to be considered.
we do not have enough time to evaluate them now,

I have just thought of your sugguestion again.
Maybe we can open the authority of local API that let the energy data can be refreshed every 1 sec in the local API.
I will discuss this with my development colleagues today.

Thanks for your very quick and excellent customer service - it gives me confidence that I am dealing with a very professional business! 

Yes a local API that provides 1 second POWER data would be ideal - I doubt people who require less than 6 seconds would need it from the cloud as they'd get it from the local network. I noticed in your reply you mentioned Energy - just to be 100% clear I don't want 1 second access to Energy, I need POWER.

I'll await your feedback :) 

laoliu

I have just thought of your sugguestion again.Maybe we can open the authority of local API that let the energy data can be refreshed  every 1 sec in the local API.I will discuss this with my development colleagues today.

Because of the problem I listed in the above pics.
We probably won't provide fast uploading version firmware recently.

It is a compromised method that provides faster-refreshed data(both energy and power) in local API.

If the customer needs to upload the data to their own server, they can develop a simple "bridge" software.
1 get json data every 1 sec
2 publish the json data to their own server.

Sorry to resurrect an old thread - I am still thinking to buy a IAMMETER but only if it can support my need.

I notice that it is now possible to alter the mqtt upload frequency. The default example in your documentation shows 12 seconds.

Can you please advise if it can publish mqtt power every 1 second? If not, what is the fastest? I know MODBUS can do 1 second, I would prefer to use mqtt if that supports 1 second updates?

we will discuss your requirements and reply to you later.

Thanks @laoliu this is excellent news!

Will this be a different firmware than standard, where would I download it please. I assume it will work on the single phase and 3 phase meters?

Thanks

Ian

We will release this special version 1 week later.
yes, it is a "special version" temporarily, base on the testing result ,we will decide whether we would merge it into the release version .
Yes, it would work for all of our energy meters (both 1phase and 3phase meter), except WEM3162.