Determining current direction on V4 with State_Watts_Dir

For more advanced meter data users. Learn from others and ask questions about how to read meters, how to use the EKM Push Data, and how to display the meter data in useful ways.
Post Reply
dgh853
Posts: 11
Joined: Sat Apr 12, 2014 4:33 pm
Contact:

Determining current direction on V4 with State_Watts_Dir

Post by dgh853 » Wed Jul 08, 2015 3:36 pm

Hi,

I'm having trouble getting my EKM to present current direction correctly on pvoutput.

Apparently pvoutput uses the State_Watts_Dir variable to determine the direction of the current.

I can see values for State_Watts_Dir such as 1,2,5, 6,7 & 8 at various times of the day depending on solar generation and consumption.

Can you please confirm what each of these values represents and whether they alone are sufficient to determine the direction of the Total Watts value.

This is for meter 300000484.

Thanks,
David
EKM Omnimeter Pulse V4 @ 415V 3 phase

Jameson
Posts: 764
Joined: Fri Nov 04, 2011 7:42 pm
Location: Santa Cruz, CA
Contact:

Re: Determining current direction on V4 with State_Watts_Dir

Post by Jameson » Wed Jul 08, 2015 4:35 pm

Here is the bitmap for Omnimeter Pulse v.4 real-time direction of current on each line:

Line1/Line2/Line3
Forward/Forward/Forward = 1
Forward/Forward/Reverse = 2
Forward/Reverse/Forward = 3
Reverse/Forward/Forward = 4
Forward/Reverse/Reverse = 5
Reverse/Forward/Reverse = 6
Reverse/Reverse/Forward = 7
Reverse/Reverse/Reverse = 8

Total Watts is not the value you want to know the direction of (this is always a positive value). You will want to know Net Watts. Yes, the bitmap above is enough to determine the value of Net Watts and to know if it is a positive or negative number. More explanation of Net Watts and some examples here: http://forum.ekmmetering.com/viewtopic. ... atts#p6243

Let me know if you would like a hand with this using your own data. I have not taken a look at how pvoutput.org is doing their Net Watts calculations yet, do you have an example or screenshots?

Thanks,
Jameson
EKM METERING
http://www.ekmmetering.com
831.425.7371

Jameson
Posts: 764
Joined: Fri Nov 04, 2011 7:42 pm
Location: Santa Cruz, CA
Contact:

Re: Determining current direction on V4 with State_Watts_Dir

Post by Jameson » Wed Jul 08, 2015 5:02 pm

I wanted to provide you with a "Net Meter" sample data set. This Push connected meter is metering a residence at the point of the Utility Meter. The residence has solar generation, so the meter sees both Forward Watts (when the residence is using more power from the grid than it generates) and Reverse Watts.

http://io.ekmpush.com/readMeter/v4/key/ ... /300001290

Here is the Widget for this meter with Watts on L1 and L2, Total Watts, and State_Watts_Dir:

http://widget.ekmmetering.com/EKM2/?rea ... _watts_dir

Right now as I am looking at it the State_Watts_Dir is at 7 (the sun is still shining) State_Watts_Dir should go to 1 or 2 when the sun goes down and residence starts to consume more power at night.

As a curiosity if you want to see the solar only generation (not Net Watts) portion of this residence it is this sample data set here:

http://io.ekmpush.com/readMeter/v3/key/ ... ters/17507
Jameson
EKM METERING
http://www.ekmmetering.com
831.425.7371

dgh853
Posts: 11
Joined: Sat Apr 12, 2014 4:33 pm
Contact:

Re: Determining current direction on V4 with State_Watts_Dir

Post by dgh853 » Mon Jul 13, 2015 4:08 pm

Thanks Jameson.

Based on these values I think the EKM is working just fine but pvoutput seems to be handling the values incorrectly when it tries to generate a consumption figure from generation (SMA Webbox) and the EKM Net. I will follow up with them to confirm they are handling the values correctly and generating the consumption values with the right delay. Thanks for your help.
EKM Omnimeter Pulse V4 @ 415V 3 phase

Post Reply