Comments for SRA Lab

Comment on Current Tranformer by Jim Kyner

Jim Kyner — Sat, 18 Jun 2011 14:57:00 +0000

Electronic ballasts for some lights can have relatively low power factor (VARs as well as KW are being drawn) which means some power is fed back to the grid (which consumers aren’t charged for). A simple current transformer (CT) measurement can be misleading. Get a power meter (e.g. Kilawatt, WattNode etc.) that can give you a better idea of your true power consumption.

Comment on Current Tranformer by Jim Kyner

Jim Kyner — Sat, 18 Jun 2011 14:51:00 +0000

Good point. Real energy (watt-hours) can’t be measured by a CT alone. A power meter that measures voltage and current simultaneously that can distinguish watt-hours from VAR-hours is needed since consumers are charged for watt-hours, not VAR-hours.

Comment on Current Tranformer by Stéphane Raimbault

Stéphane Raimbault — Sun, 29 May 2011 20:13:00 +0000

Yes, the cos Phi is useless as I’ve explained!

For `direct current’, you’re right I’ve used a multimeter to measure the transformer output and it’s just a voltage step down (AC) in this case.

Comment on Current Tranformer by jpc

jpc — Sun, 29 May 2011 00:19:00 +0000

I do not understand what the cosphi of your electricity provider has to do with anything.

Btw. AFAIK this is a normal transformer (why “current”?) and the lamps do not need “continuous” current. They just need a voltage step down from 220V (or 110V) to 12 or 24V.

Comment on Succès pour les premières rencontres Django FR ! by La DjangoCong 2011 est terminée « SRA Lab

La DjangoCong 2011 est terminée « SRA Lab — Mon, 18 Apr 2011 08:28:15 +0000

[...] à Makina Corpus, j'ai pu assister à nouveau à la DjangoCong. Cette une occasion idéale pour retrouver l'équipe des Djangonautes de Makina au [...]

Comment on New libmodbus 2.9.2 with win32 support and backends by Stéphane Raimbault

Stéphane Raimbault — Sun, 27 Feb 2011 22:08:01 +0000

The branch you mentions on launchpad wasn’t designed to merge upstream and the author didn’t contact me in this goal.
Anyway I’ve recently received feedback from a VS 2008 user and applied a change on git master:

https://github.com/stephane/libmodbus/commit/3fb246237df40e25ed9e1c24a34c0779778e79e6

Could you try the git version and report if it works for you?
I’m not able to test with VS so I need testers (see https://github.com/stephane/libmodbus/wiki/Call-for-Testers)

Comment on New libmodbus 2.9.2 with win32 support and backends by Tobi

Tobi — Thu, 24 Feb 2011 13:37:24 +0000

Hi Stephane,

the current version of libmodbus doesn’t compile on Visual Studio 2008. Do you plan to support the Visual Studio Compiler too? I tested this branch:
https://code.launchpad.net/~thepyper/libmodbus/win32-native
and it works perfectly. Or do I have to change the compile settings?

Thank you very much for this great library!!!
Tobi

Comment on Current Tranformer by Stéphane Raimbault

Stéphane Raimbault — Fri, 18 Feb 2011 21:51:45 +0000

Yes you can use libmodbus to talk with your device, you need v2.9.3 which offers a Windows support.

Comment on Current Tranformer by Armin

Armin — Mon, 14 Feb 2011 16:52:45 +0000

Hello Stephane,
we’re using WiLEM to monitor our Power Consumption.
http://www.lem.com/hq/en/content/view/279/218/
The MeshGateway offers a serial Port (RS232) where the Modbus RTU data stream is hookes up to the computer.
How can we use your driver within our C++ application – all in Win32 (sorry).

Comment on LVM – Incorrect metadata area header checksum by emman

emman — Thu, 16 Dec 2010 13:51:15 +0000

thanks for this nice post