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Data Logging

Data Logging

(OP)
I have to log pH and ORP stuff on a continual basis.
What are we using for data collection these days?

I think this is going to be 4-20mA or 0-5V. I can see that this will probably grow to more than two data stream too.

Eventually I'd also like to retrieve it wirelessly if possible so while the logger is logging I need to also be able to read it out.
A PLC Modbus crazy PLC will likely be involved too if that can be useful.

Keith Cress
kcress - http://www.flaminsystems.com

RE: Data Logging

Sample rate?

Mike Halloran
Pembroke Pines, FL, USA

RE: Data Logging

(OP)
Let's say 8 channels every minute.
24Hrs x 60Minutes x 8ch

Likely 12bit data i.e. 2 bytes.

24x60x2 = 2880 bytes per day.

Preferably holding a month's data
2880 x 30 days = 100k of storage.

Keith Cress
kcress - http://www.flaminsystems.com

RE: Data Logging

(OP)
Hi IR,
No not specifically OTS but that would probably be my first choice. There are other things going on that might make Arduinos/Raspberrys useful in these applications too so I'm certainly willing to entertain them.

Have you used either of them for data logging or even just analog inputs of any type with them?

Keith Cress
kcress - http://www.flaminsystems.com

RE: Data Logging

The Arduino on its own is not bad for data acquisition of single-ended signals, but lacks onboard storage. It's not fantastically fast either, though I don't see that being a problem for the sort of job you're looking at. By the time you've added a shield with an SD card and another one to carry your analog scaling and buffering networks, the heap looks a bit ungainly (while remaining cheap as chips)



If the basic Arduino Uno doesn't have enough channels for your needs, there are larger models for only slightly less cheapness.

The Pi has no onboard A to D, so you'll need a shield to do that (and things like the Gertboard only have two A to D channels) - as well as scaling and buffering. I could only ever see me using it for data logging in conjunction with an OTS USB DAQ pod.



A.

RE: Data Logging

No...
Go old school:


wink
Sutron 8210
I'm using one for basically the same purpose, myself, and I have a few spares. Free if you pay shipping (North America)
I read all of your requirements above. It does everything you want (you aren't asking for much!)

STF

RE: Data Logging

(OP)
zeusfaber; Those ME-RedLabs look pretty nice. Perhaps a bit hard to get in the USA.

Spar; Those Sutrons look really well thought out and supported. You sure don't see manuals like that these days!
I'm intrigued. That might actually work. I appreciate the offer! What do you think postage would be to... say, San Fransisco?

Keith Cress
kcress - http://www.flaminsystems.com

RE: Data Logging

smoked, you can find similar stuff at my link too. In fact, they look like they come from the same chinese supplier, except the danes get theirs in red plastic instead of black...

RE: Data Logging

Actually, those are licensed versions of the mccdaq products, they use the same software titles and everything.

RE: Data Logging

itsmoked,
If you are seriously interested, please read:

http://www.fieldlines.com/index.php/topic,148892.m...

You can contact me through that website, or through means available with Eng-Tips, or at the "obvious" URL. Make sure to append .ca not .com.

STF

RE: Data Logging

(OP)

Quote:

Actually, those are licensed versions of the mccdaq products, they use the same software titles and everything.

Huh,I didn't see any that looked too similar I need to look again.


SparWeb; Thanks for the FLs link. I'll contact you.

Keith Cress
kcress - http://www.flaminsystems.com

RE: Data Logging

The red ME-Redlab boxes are Minilab 1008 modules. We use a bunch of them in test here. They have 4 differential or 8 single ended analog inputs. The 37 pin d-sub connector on the end is a bunch of digital I/O.


RE: Data Logging

(OP)
Thanks LH! I wasn't finding those. They certainly do appear to be the RedLab in a BlackLab sort of way. That's at a price-point that's more palatable too.

Keith Cress
kcress - http://www.flaminsystems.com

RE: Data Logging

Been away.

Lionel and BTrueblood are right - although I know there's another American firm that claims that the Minilab 1008 is in turn a copy of one of its own products.

A.

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