Low Electrical Energy Meter EMK850S+

[randyswift]

Hi all,

This is a product placement, you can skip this post if you don't like.

I got a piece of new equipment recently, a power monitor EMK850s+ from a company named Rejoe Technology, I think it is worth some time for a review. 

For now, I have just tested a wireless communication module and my wireless mouse, it works just fine for me.

1. Output Voltage - Official description: 0.5 - 12 V

It satisfies a maximum output of 12V and the minimum output of 0.5V. I lower the output under 0.5V, it still works fine, but the 0.2V is the real minimum output. 

The output voltage has a deviation range from -0.08V to 0.02V. It depends on your tolerance whether this power monitor is acceptable. However, the output voltage is rather stable under the test period, if you want a precise value, you will need a multimeter to assist you.

Read the pdf (attachment 1) for more details.

2. Sample rate - Official description: 10 ksps

From the data that I have access to, I assume it has a sample rate of around 9 ksps. See the CSV files (attachment 2), it shows 8 or 9 samples per 0.001 millisecond.

For some reason, the software can only extract the data across the display window, if I modified the time axis to show more data, the minimum time interval of the recorded data will increase, therefore the more data I want to extract to a CSV file, the poorer the time precision it will be. Since that, I can only estimate the sample rate by the extracted CSV file that has the highest precision (attachments 2 ).

To speak of, to draw the graph in the software display window, it will display the data after calculation. You can clearly see in the video (attachment 3) that the graph will have more details if you zoom in.

3. Current measure range and accuracy - Official description: 0.1μA - 2A, 1%±1μA

According to the data collected by the software (attachment 4), its minimum scale value is at least more precise than 0.1 μA.

As for the current measurement range, I don’t have enough DUT that will satisfy the measurement.

4. Summary

In general, this power monitor matches the official description. In my opinion, its advantages are 12V output voltage which allows more usage scenarios, high precision, and is equipped with the software.

I haven’t used it for a long time, I will update if problems come up in the future. I am not sure everyone needs to cost 600 dollars to buy one, but this low electrical energy meter meets my expectation.

This is just a rough review, hope it can help you.

Product: https://amzn.to/3HlRILr

Demo:

[kaz911]

$600 sounds like a lot compared to what else is available on the market and how mature the software is. If it was HK$600 it might be more relevant.

There is Otti Power and JouleScope for almost the same price - with Multiplatform software and a few years more behind them.

Here is a good breakdown of current low power monitors available : https://pallavaggarwal.in/dc-current-analyzer-for-embedded-iot-product-development/#1_Joulescope_799

And to be honest - based on your writing - it sound a lot like the sentence structures from the video demo and it is your first post So are you from Rejoe and this is just "product placement?" - if so - it is probably slightly better in this forum to be up front about it.

[randyswift]

Thanks for the advice.

[Kean]

And to be honest - based on your writing - it sound a lot like the sentence structures from the video demo and it is your first post So are you from Rejoe and this is just "product placement?" - if so - it is probably slightly better in this forum to be up front about it.

It seems quite suspicious based on the fact another new account "rejoetech" also has just posted about this device.
https://www.eevblog.com/forum/buysellwanted/pricing-survey-power-profiler-emk850s/

Oh... I see "randy" went back and edited the original post above to now state it is a "product placement".   

[rejoetech]

Our original intention was to introduce our product to the community from a real, objective perspective and try to tell the features and disadvantages of the device so that our device can find its way to its most suitable users. The last thing we want to see is that our customers find out that our device is useless to them. We won't lie about anything about our product, that's for sure.

After we see the comment from kaz911 which we found very constructive, we begin to post through the company's name and started a pricing survey based on the advice from kaz911, that's what your link refers to.

We are new to the community, but we are open-minded to any advice for improvement and we treasure every opinion from the community.

Thanks for the criticism. We are sorry for the inconvenience caused to the community. We will be more cautious and promised to the rules when posting at the forum in the future.