SRA Lab - Latest Comments

Re: libmodbus for Arduino (almost!)

Stéphane Raimbault — Fri, 23 Mar 2012 04:49:35 -0000

I would be great but Arduino doesn't provide a real OS. Rasberry Pi, yes!

Re: libmodbus for Arduino (almost!)

Dominic Storey — Mon, 19 Mar 2012 15:48:17 -0000

HI Stephane,

Any plans to port 3.0.2 to Arduino? There's plenty of room on a Mega!
Dominic

Re: Magic libmodbus 3.0.0 is out

Андрей Кравчук — Mon, 05 Mar 2012 22:15:34 -0000

> You've just a problem in your setup.
Well, that's right.

> master contains the code of next modbus 3.2
Oh, that's the point.

Re: Magic libmodbus 3.0.0 is out

Stéphane Raimbault — Sun, 04 Mar 2012 06:47:01 -0000

The default branch is master! And currently, master contains the code of next modbus 3.2. You've just a problem in your setup.

Re: Magic libmodbus 3.0.0 is out

Андрей Кравчук — Sat, 03 Mar 2012 12:08:43 -0000

Why don't you made 3.0 the default branch on github yet? That's confusing, you know - I've git submodule'd libmodbus in my new project and just discovered that I'm using old 2.0 instead of brand new 3.0 :(
(Sorry my bad English)

Re: libmodbus for Arduino (almost!)

Juan — Sun, 19 Feb 2012 12:35:15 -0000

Have you tried SimpleModbus? and why do you say the code is ugly?

Re: Emacs, cut & paste and nice other hotkeys

Kshitij Gaipal Ŧ — Wed, 02 Nov 2011 11:01:01 -0000

"(define-key isearch-mode-map [(control f)] (lookup-key isearch-mode-map "\C-s"))"This line is what I was looking for ... it makes continuous hitting Control+f to search forward.... you made my day man... thnx!!

Re: Incredible coincidence

regilero — Mon, 03 Oct 2011 09:38:34 -0000

Redirections in ajax are always hard to maintain cross-brosers. There's 2 intersting resources on that on Stack Overflow:

http://stackoverflow.com/quest...

One of the way to obtain a really cross browser behavior is then to manage a subset of HTTP in the xhr http protocol (code 200). And to manage 404,500,302 error codes in the json content/js code. Very useful to extend it to functionnal behaviors (like end of session management where your html block get filled by the login page).

Re: Current Tranformer

Jim Kyner — Sat, 18 Jun 2011 10:57:31 -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.

Re: Current Tranformer

Jim Kyner — Sat, 18 Jun 2011 10:51:33 -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.

Re: Current Tranformer

Stéphane Raimbault — Sun, 29 May 2011 16:13:46 -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.

Re: Current Tranformer

jpc — Sat, 28 May 2011 20:19:24 -0000

I do not understand what the cos\phi 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.

Re: New libmodbus 2.9.2 with win32 support and backends

Stéphane Raimbault — Sun, 27 Feb 2011 17:08:01 -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/li...

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/li...

Re: New libmodbus 2.9.2 with win32 support and backends

Tobi — Thu, 24 Feb 2011 08:37:24 -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/~th...
and it works perfectly. Or do I have to change the compile settings?

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

Re: Current Tranformer

Stéphane Raimbault — Fri, 18 Feb 2011 16:51:45 -0000

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

Re: Current Tranformer

Armin — Mon, 14 Feb 2011 11:52:45 -0000

Hello Stephane,
we're using WiLEM to monitor our Power Consumption.
http://www.lem.com/hq/en/conte...
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).

Re: LVM – Incorrect metadata area header checksum

emman — Thu, 16 Dec 2010 08:51:15 -0000

thanks for this nice post

Re: libmodbus

terry — Thu, 02 Dec 2010 01:20:35 -0000

Hi I want to down load the modbus source code for learning.

thanks a lot.

Re: LVM – Incorrect metadata area header checksum

herbert — Mon, 29 Nov 2010 00:20:51 -0000

I currently running openfiler 2.3 and With 2 ext3 partitions and 3 iscsi partitions. The problem began last sat when I can’t connect to the ISCSI partitions anymore. I tried delete the ISCSI partition and recreate them. Still same error SCSI Serial No. and SCSI ID "Incorrect metada".. So I removed all the ISCSI partitions. The system still showing this error

Incorrect metadata area header checksum
Found volume group "datastore_01" using metadata type lvm2
Found volume group "datastore_02" using metadata type lvm2

datastore01 and datastore02 is the two ext3 partitions and they seem working fine (I can read and write). Can you point me the right direction for a solution to fix this problem?

Re: Current Tranformer

Stéphane Raimbault — Mon, 22 Nov 2010 03:58:06 -0000

The measures have been done before the transformer so we don't need to take care about the energy efficiency of the transformer to measure the consumption!
To be even more precise, I've supposed a theorical cos phi of 1 because the real cos phi of my electricity provider is around 0.93 (EDF), so the final result is really near the theorical cos phi, so 40 VA is P=0,18*230*0.93 = 38.5W (only 1.5W of difference). Doesn't really change anything? I don't think so.

Re: Current Tranformer

NiTr0 — Tue, 16 Nov 2010 05:33:36 -0000

Your transformer consumes 40VA, not 40W - you forgot about power factor, which is far away from 1 for 'electronic transformers' (that are used mainly in such applications), and is close to 1 for classical transformers.

Re: libmodbus

Stéphane Raimbault — Thu, 04 Nov 2010 04:42:40 -0000

Yes, libmodbus deals with endianess.

Re: libmodbus

bob — Wed, 03 Nov 2010 21:45:43 -0000

Hi,

Does this library deal with endianess? I need to run this code on a big endian machine. I'm not a modbus expert, but my googling tells me modbus is inherently big-endian so i don't think it would be a problem since it works on my little endian laptop.

Thanks for the good work.

Re: libmodbus

Stéphane Raimbault — Tue, 28 Sep 2010 07:20:49 -0000

The slave ID used in modbus_new_rtu identifies your device (server or slave, it depends on what do you do after) and the slave ID in modbus_set_slave(), sets the ID of the slave you want to query.

Feel free to propose a clearer API, on my not very happy with this.

Re: libmodbus

compplusplus — Thu, 09 Sep 2010 06:37:51 -0000

And why in mb = modbus_new_rtu(“/dev/ttyS0″, 19200, ‘N’, 8, 1, 1); slave id = 1
and in modbus_set_slave(mb, 10); sale id = 10?