How to Get Water and Gas Data from Omnimeter

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danieltien
Posts: 1
Joined: Sun Dec 26, 2021 9:49 pm

How to Get Water and Gas Data from Omnimeter

Post by danieltien »

Hi All,

I'm trying to grab water and gas use data from our rental property (we already have separate electrical service)--we're planning on installing EKM meters for water (State of California SB7 law requires us to use submeters separate from the main unit) and gas.

The plan is to wire the meters to the Omnimeter and then poll the Omnimeter with a Raspberry Pi Pico and transmit the data using a low-data rate IoT cellular system (LTE-M). I had originally considered the EKM Push 3 as a simpler off-the-shelf solution, but I don't need realtime data and can't justify the monthly data costs that would require. I only need usage data in order to calculate the monthly gas and water bill, which should be no more than a megabyte of data traffic a month. (IoT data plans are as low as $3 a month)

All of the example data dictionaries and sample output digests provide a wealth of information on power, but nothing on gas or water. Presumably it would be Pulse Count1 and 2 and the ratios, since the meters themselves would transmit pulses to the Omnimeter, but all of the examples posted show zeroes.

I suppose I could also obviate the Omnimeter and just have the Pico count the pulses, but that's a level of complexity I don't have time to explore at the moment (Future project). At the moment, I'd rather have the Pi Pico use the RS-485 adapter and use a MicroPython script to poll the Omnimeter, parse the data and push it over LTE once a week. I can't install the meters in the unit until I have something workable, but I don't have any means of safely simulating gas or water use with the meters.

I'm happy to post progress to the forum and publish the code and schematics on github once it's at an operable level of development. Any help in grabbing and parsing the data would be welcome.

Thanks
Jameson
Posts: 812
Joined: Fri Nov 04, 2011 7:42 pm
Location: Santa Cruz, CA
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Re: How to Get Water and Gas Data from Omnimeter

Post by Jameson »

Thats great! Sounds like a very cool project.

Yes, you could either use the EKM Omnimeter Pulse v.4 to count the pulses from up to 3 separate pulse output devices, then read the Omnimeter Pulse with either your Pico, or with our EKM Push3. Or you could count the pulses directly using your Pico.

If you decide to read your Omnimeter with your Pico, we do provide the RS485 protocol, so that you can read your Omnimeter with your Pico over RS485: https://documents.ekmmetering.com/api-d ... unications Yes, you would just parse out the Pulse Counts from Input 1, Input 2, and Input 3.



If you decide to use an EKM Push3 you can either gather the data you need from the cloud, or locally using the local API to the EKM Push3 gateway. If you want to connect the Push3 to the web, you can probably find a cellular data service for something in the neighborhood of $10 per month for unlimited data. That is what we are using with our Teletonika cellular modem: https://www.ekmmetering.com/collections ... ika-rut240
But like you say, if you can do it with LTE-M, that sounds awesome too. LoraWAN might also be an option.


If you want to count the pulses with your own pico, there are examples of this on GitHub for various devices. Here is a conversation about using a Raspberry Pi to count pulses on this forum: viewtopic.php?f=9&t=6128&p=10823&hilit= ... +pi#p10823


You said: "but I don't have any means of safely simulating gas or water use with the meters.”, you can simulate a pulse just by touching the two wires together that are connected to the pulse input of the Omnimeter Pulse v.4

Thats great that you would offer to post your progress to the forum here, Im sure there will be others that will be interested to follow what you have come up with (me being one of them), so yes, please keep us posted! Yes, I would also be happy to help with parsing the data. You should check out our EKM Dash software, once you are reading your Omnimeter with the EKM Dash, you can go to Help > Hex Inspector, to “see” how the Dash reads the Omnimeter and parses the meter data: https://help.ekmmetering.com/support/so ... -inspector
Jameson
EKM METERING
http://www.ekmmetering.com
831.425.7371
Jameson
Posts: 812
Joined: Fri Nov 04, 2011 7:42 pm
Location: Santa Cruz, CA
Contact:

Re: How to Get Water and Gas Data from Omnimeter

Post by Jameson »

Here is a screenshot from my EKM Dash Hex Inspector. It shows an example of an Omnimeter Pulse v.4 Read A and a Read B. I have highlighted (in faint blue color) the section of the Hex that is for the Pulse Count 1, Pulse Count 2, Pulse Count 3. The Hex for this section at this moment is 30 30 30 30 32 30 37 32 30 30 32 32 37 35 34 38 30 30 30 30 30 30 30 33. You can see that the Hex inspector also parses out the data (to help teach you how to parse the data yourself), the parsed data says: Pulse_Cnt_1: 2072, Pulse_Cnt_2: 227548, Pulse_Cnt_3: 3
Screen Shot 2022-01-03 at 5.30.32 PM.png
Screen Shot 2022-01-03 at 5.30.32 PM.png (735.34 KiB) Viewed 3457 times
Jameson
EKM METERING
http://www.ekmmetering.com
831.425.7371
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