Bristol Digest, Vol 518, Issue 5

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Today's Topics:

1. Re: Controlling valves (David Smith)
2. Re: Controlling valves (David Smith)
3. Re: Controlling valves (Andrew)
4. Re: Controlling valves (Andrew)
5. Re: Controlling valves (david)
6. Re: Controlling valves (Alaric Snell-Pym)
7. Re: Controlling valves (Administrator)


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Message: 1
Date: Thu, 26 Sep 2013 15:40:31 +0100
From: David Smith <Dave.Smith@st.com>
To: <bristol@mailman.lug.org.uk>
Subject: Re: [bristol] Controlling valves
Message-ID: <5244475F.3020709@st.com>
Content-Type: text/plain; charset="ISO-8859-1"

On 09/26/13 15:37, Andrew wrote:
> Ok. Thanks. My only experience of writing drivers was at low level for
> some hot swap RAID boxes and it got ferociously complex very quickly!

That's why I think Arduino is your best bet - the underlying "complex"
stuff is already wrapped up by the programming environment so you can
just focus on what you actually want to achieve.





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Message: 2
Date: Thu, 26 Sep 2013 15:47:45 +0100
From: David Smith <Dave.Smith@st.com>
To: <bristol@mailman.lug.org.uk>
Subject: Re: [bristol] Controlling valves
Message-ID: <52444911.9090706@st.com>
Content-Type: text/plain; charset="ISO-8859-1"

On 09/26/13 15:31, Andrew wrote:
> It is for a long term use; and reliability is an issue once it is up and
> running. It's all very low key. Low pressures, not a lot of on and offs.
> I assume relays would be ok.

In which case, if you're going to use relays, check their operational
lifetime. Let's say you're going to operate them once every 5 seconds,
24 hours a day. That's over 6 million operations per year, and is well
beyond the MTBF of many relays.



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Message: 3
Date: Thu, 26 Sep 2013 15:57:04 +0100
From: Andrew <andrewsoltau@gmail.com>
To: Bristol and Bath Linux User Group <bristol@mailman.lug.org.uk>
Subject: Re: [bristol] Controlling valves
Message-ID: <52444B40.10900@1dtv.com>
Content-Type: text/plain; charset="iso-8859-1"; Format="flowed"

On 26/09/13 15:40, David Smith wrote:
> On 09/26/13 15:37, Andrew wrote:
>> Ok. Thanks. My only experience of writing drivers was at low level for
>> some hot swap RAID boxes and it got ferociously complex very quickly!
> That's why I think Arduino is your best bet - the underlying "complex"
> stuff is already wrapped up by the programming environment so you can
> just focus on what you actually want to achieve.
>
>
Thanks

Sounds like just what I'm looking for.

Andrew


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Message: 4
Date: Thu, 26 Sep 2013 15:58:13 +0100
From: Andrew <andrewsoltau@gmail.com>
To: Bristol and Bath Linux User Group <bristol@mailman.lug.org.uk>
Subject: Re: [bristol] Controlling valves
Message-ID: <52444B85.3050907@1dtv.com>
Content-Type: text/plain; charset="iso-8859-1"; Format="flowed"

On 26/09/13 15:47, David Smith wrote:
> On 09/26/13 15:31, Andrew wrote:
>> It is for a long term use; and reliability is an issue once it is up and
>> running. It's all very low key. Low pressures, not a lot of on and offs.
>> I assume relays would be ok.
> In which case, if you're going to use relays, check their operational
> lifetime. Let's say you're going to operate them once every 5 seconds,
> 24 hours a day. That's over 6 million operations per year, and is well
> beyond the MTBF of many relays.
>
> _______________________________________________
Cheers

They won't be getting that kind of use. We just want to automate a
simple but tedious routine of operations that will be carried out a few
times a day at most.

Andrew


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Message: 5
Date: Thu, 26 Sep 2013 15:59:57 +0100
From: david <david@avoncliff.com>
To: bristol@mailman.lug.org.uk
Subject: Re: [bristol] Controlling valves
Message-ID: <52444BED.8060005@avoncliff.com>
Content-Type: text/plain; charset=UTF-8; format=flowed

On 26/09/13 15:36, Andrew wrote:
> Hi David
>
> On 26/09/13 15:21, david wrote:
>> It depends on the scale, I am doing a lot of this commercially using
>> Labview.
>> That is a expensive National Instruments product.
> Looking at their site this looks great.
>> But some years ago they did give away a Linux version, which can still
>> be downloaded from a German site. It is good and powerful, but has
>> quite a learning curve.
> That sounds ideal. But a bit of googling only turned up this forum post
> which concluded there was nothing like that available:
>
> http://forums.ni.com/t5/LabVIEW/from-where-can-i-donwload-labview-for-Ubuntu-10-04/td-p/1250354
>
http://forums.ni.com/t5/LabVIEW/labview-6-1-linux/td-p/1741200
Says it is official, but only for home use in Germany, I would check the
license on the download.
ftp://ftp.heise.de/pub/ct/spezial/labviewlinux.zip? is working

>> Labjack do some interface boxes with labview drivers for < ?100
> That sounds just the job.
>>
>> However I would recommend starting on the Raspberry, looking at the
>> home robotics shops, and use Python or any language you are happy with.
>> David
> Thanks
>
> Any thoughts on pi vs arduino?
>
Well I would go raspberry, because extra features might be handy one
day. Much easier to do remote control from your phone, and networking in
general. And I have found the i/o control easy to use from C.
But if it will always be a stand alone box, with simple push button
control then arduino is good and has lots of support for hardware projects.




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Message: 6
Date: Thu, 26 Sep 2013 16:29:53 +0100
From: Alaric Snell-Pym <alaric@snell-pym.org.uk>
To: bristol@mailman.lug.org.uk
Subject: Re: [bristol] Controlling valves
Message-ID: <524452F1.1020405@snell-pym.org.uk>
Content-Type: text/plain; charset="utf-8"

On 26/09/13 15:59, david wrote:

>> Any thoughts on pi vs arduino?
>>
> Well I would go raspberry, because extra features might be handy one
> day. Much easier to do remote control from your phone, and networking in
> general. And I have found the i/o control easy to use from C.
> But if it will always be a stand alone box, with simple push button
> control then arduino is good and has lots of support for hardware projects.
>

I'd second that.

1) You'll be able to get going quicker on the arduino - less
infrastructure. All the tools required to start waving I/O lines about
are there in the standard setup.

2) Smaller, simpler, cheaper, lower-power device to put into your final
project

3) Lots of easily accessible I/O lines, off the shelf "shields" to do
stuff like driving relays or high-current driver transistors

I assumed, with your talk of prototyping on a PC then using a Pi, you
were going to be requiring beefy computer resources such as filesystem
mass storage, networking, or video output - otherwise I'd have suggested
the arduino too!

ABS

--
Alaric Snell-Pym
http://www.snell-pym.org.uk/alaric/

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Message: 7
Date: Thu, 26 Sep 2013 17:56:06 +0100
From: Administrator <administrator@startext.co.uk>
To: andrew@1dtv.com, Bristol and Bath Linux User Group
<bristol@mailman.lug.org.uk>
Subject: Re: [bristol] Controlling valves
Message-ID: <52446726.5030608@startext.co.uk>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

On 26/09/13 14:40, Andrew wrote:

> I have been asked to do a project which involves using the pc to turn on
> and off some valves with reasonably accurate timing. I would be grateful
> if someone could point me in the right direction.

Mmm.

Which country are you planning on paralysing, did you say ?
--
Martin Wheeler - Glastonbury - England
mwheeler @ startext.co.uk
http://martinwheeler.co.uk/



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End of Bristol Digest, Vol 518, Issue 5
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