<![CDATA[Energy Meter kwh Reset]]>Hi All,

I have an energy meter I am using, connected via Modbus. The issue I have is the kwh figure in the meter can not be reset to zero, currently it is up to 9124.0 kwh. When I start a new test I'd like to reset the logged kwh figure.

7fbe7db3-9179-45e0-8f23-2afcb22620ff-image.png

What is the best way of doing this via the REX program? I wondered about saving the last know value from the Modbus register and then subtracting that to give me a virtual reset and start from zero again.

Thoughts?

Cheers

Mike

]]>https://forum.rexygen.com/topic/231/energy-meter-kwh-resetRSS for NodeMon, 10 Aug 2026 23:55:21 GMTTue, 23 Mar 2021 23:11:37 GMT60<![CDATA[Reply to Energy Meter kwh Reset on Thu, 25 Mar 2021 18:41:49 GMT]]>Hi Both,

Thank you. @Apollo, great tip. That will save me loosing data.

Cheers

Mike

]]>https://forum.rexygen.com/post/920https://forum.rexygen.com/post/920Thu, 25 Mar 2021 18:41:49 GMT<![CDATA[Reply to Energy Meter kwh Reset on Thu, 25 Mar 2021 10:16:49 GMT]]>Hi guys,
@mikeyh you're welcome. @apollo is right with persistent parameters. If you don't just do short-term tests, don't forget to turn persistent parameters on.

]]>https://forum.rexygen.com/post/918https://forum.rexygen.com/post/918Thu, 25 Mar 2021 10:16:49 GMT<![CDATA[Reply to Energy Meter kwh Reset on Thu, 25 Mar 2021 06:03:54 GMT]]>@mikeyh

Maybe you can also make the parameters of function block SHLD non-volatile (Persistent parameters).

If you restart your computer and/or download new program then it will not lose the previous stored value.

6a0f7a3c-42b6-4b34-aebe-9fca0327af0a-image.png

And storing the value every midnight in a database and then trigger the SETH input would give you a nice overview of the daily consumption.

]]>https://forum.rexygen.com/post/917https://forum.rexygen.com/post/917Thu, 25 Mar 2021 06:03:54 GMT<![CDATA[Reply to Energy Meter kwh Reset on Thu, 25 Mar 2021 04:27:53 GMT]]>@reitinge Hi Jan,

That works extremely well, even better once made into a small subsystem! Thank you for your help as always.

Cheers

Mike

]]>https://forum.rexygen.com/post/915https://forum.rexygen.com/post/915Thu, 25 Mar 2021 04:27:53 GMT<![CDATA[Reply to Energy Meter kwh Reset on Wed, 24 Mar 2021 07:17:58 GMT]]>@mikeyh Hi Mike,
one possibility is to use a SHLD block with Triggered sampling mode (documentation here). When you send a pulse to the block input SETH, the current value of input u is stored at output y. The overall connection can then look something like this:
a6aff46e-8b4e-426d-863d-452549f0874b-image.png

Cheers,
Jan

]]>https://forum.rexygen.com/post/911https://forum.rexygen.com/post/911Wed, 24 Mar 2021 07:17:58 GMT