In the market for a multichannel TC datalogging thermometer

[HAL9000]

...and I found this one:

http://www.omega.com/Temperature/pdf/HH506A_HH506RA.pdf

[EDITED wrong link]

Accuracy and sample rate seem more than adequate for measuring brew temp to me, and at a much lower cost than a comparable Fluke. FWIW I would be substituting SLE probes for the provided TCs. Seems like a very reasonable price given the alternatives.

Am I missing something?

Thanks,
Paul

[DavidMLewis]

...and I found this one:

http://www.omega.com/Temperature/pdf/HH506A_HH506RA.pdf

[EDITED wrong link]

Accuracy and sample rate seem more than adequate for measuring brew temp to me, and at a much lower cost than a comparable Fluke. FWIW I would be substituting SLE probes for the provided TCs. Seems like a very reasonable price given the alternatives.

Am I missing something?

Thanks,
Paul

No, it seems like an OK unit. I'd only add that the supplied software is execrable. I use a Mac, on which said software won't run, so I ran it on a PC and grabbed the port traffic. From this, with a little help, I was able to reverse-engineer the protocol, and brew up some Python code to deal with it. I'd be happy to supply the protocol, and the Python code too, if anybody wants it.

Best,
David

[another_jim]

It's the lowest cost usable 2 channel logger I could find.

$199 gets you this 4 channel logger:

http://store.omniinstruments.net/omnidaq4t.htm

which can stand alone, since it store 16K readings per channel. Unfortunately it's type K only. Omega sells the same unit in 2 channels for a tad less:

http://www.omega.com/ppt/pptsc.asp?ref=HH305_306&Nav=teml06

These units are better for apps where you don't want to have your computer hooked up to it all the time. It's technically feasible to hook in other types of thermocouples and convert the readings back in the computer, but a pita (a tc input just reads voltage and converts).

There's one potential gotcha. Omega's specs show a variable sample rate starting at 1 second. The Omni people told me it ran at a fixed 3 second rate.

In any case, I plan to get one after new years, and hook it to my Tea's boiler, thermosyphon in and out (nothing fancy, just with surface-contact sensors), and showerscreen, and run it all day to see what actually goes on. For this purpose a 3 second sample rate is fine.

[DavidMLewis]

It's the lowest cost usable 2 channel logger I could find.

$199 gets you this 4 channel logger:

http://store.omniinstruments.net/omnidaq4t.htm

which can stand alone, since it store 16K readings per channel. Unfortunately it's type K only. Omega sells the same unit in 2 channels for a tad less:

http://www.omega.com/ppt/pptsc.asp?ref=HH305_306&Nav=teml06

There's one potential gotcha. Omega's specs show a variable sample rate starting at 1 second. The Omni people told me it ran at a fixed 3 second rate.

The Omega manual specifies 1.25 samples per second. There's another gotcha, though, which you originally pointed out to me: the inputs use a common ground, so at most one of the probes can be grounded if they're in electrical contact with one another.

Best,
David

[HAL9000]

Omega sells the same unit in 2 channels for a tad less:

http://www.omega.com/ppt/pptsc.asp?ref=HH305_306&Nav=teml06

I was looking at that one too and came upon many under different brands that look the same, for example:

http://cgi.ebay.com/ws/eBayISAPI....em&item=7573113745

http://www.monarchserver.com/Page8-thermo-7-8-02.pdf


What surprised me about the 506RA is that, at least based on the spec sheet, it is more accurate (.05%rdg +-.3C vs. .2%rdg+-1C) and reads 2.5 times per second rather than 1.25, and yet it is $40 cheaper than the HH306. I suppose the extra storage with the 306 may be worth the tradeoff to someone, but probably not to me. Though it would be nice to see this in a 4 channel model...

Has anyone here "homebrewed" a temp logger with a DAQ or something similar?

Paul

[HAL9000]

What surprised me about the 506RA is that, at least based on the spec sheet, it is more accurate (.05%rdg +-.3C vs. .2%rdg+-1C) and reads 2.5 times per second rather than 1.25, and yet it is $40 cheaper than the HH306. I suppose the extra storage with the 306 may be worth the tradeoff to someone, but probably not to me. Though it would be nice to see this in a 4 channel model...

Thinking about it further, maybe Omega initially adopted the 306 because they were easily available (even ubiquitous) wholesale and Omega had nothing comparable "in house" to offer at the time? Note that they designate this device "Omegaette" rather than "Omega." Why the distancing?

Maybe now they are coming in with the "Omega" 506RA as an HH306 killer, looking for marketshare?

Just some speculation...

Paul

[Balthazar_B]

Any reason the HH509R would not work for this application?

http://www.omega.com/Temperature/pdf/HH508_509.pdf

[another_jim]

Any reason the HH509R would not work for this application?

http://www.omega.com/Temperature/pdf/HH508_509.pdf

Nice! Seems it needs a live connection to the computer to work as a datalogger; but otherwise it seems like a winner.

[Balthazar_B]

Its listed accuracy is not as fine as the 506, but I'm not sure that's a deal-breaker, is it?

[another_jim]

I bought the OmniDaq for $195 (aka Omega HH309 for $275) and just put it through its paces.

The unit comes in a cheap but functional carry-everything in foam rubber case which holds the unit, TCs, cables, battery. manual, software, and Mr Chang's note that he calibrated it to NIS traceable standards (there's four pots, 3 higher temps inside and the icepoint outside for your own hacking).

Use is a snap. Power-on plus other buttons (labelled) clears the memory, sets the clock or the sampling rate. Sampling starts when one hits record, stops when one hits it again. A separate file is created for each recording session including however many channels are used, plus the date and time to the second of the reading. The sampling rate is from one per second to one per 99 hours. 16K readings per channel are stored.

I tried immersing one TC in brine in an all-metal pan, heated it to boiling and touched the other TC to the top of the pan so there was a conductive path. The sensors both worked without crosstalk.

The software is just as easy as the unit. It'll load the recorded files, store them or graph them. The graphs can be printed but not saved in a graphics format (use screen-capture or a program that can decode a print-file). The file format is CSV for single files or a proprietary format for the multiple logs. The graphs can be labelled, annotated and marked. They can be formatted to print multiple lines on one Y axis, or with a separate Y-axis per channel.

The one letdown is the paleo-electronic RS232 interface; but USB converters are available for around $30.

I cannot comment about reliability; but out of the box, this unit is very nice indeed.

Omni didn't bother pasting on their logo; so the actual manufacturer is visible. They are called "Center Technology Corp" and, according to their manual, produce lots of other loggers that may be of interest. Unfortunately, their listed website and email http://www.centertec.com center@centertek.com seems to lead to some sort of "make an offer on this domain" site. For those interested on going on a Chinese easteregg hunt, they give an address: 4/F No 415, Jung-Jen Rd, 238 Shu-Lin, Taipei, Taiwan.

[Johnny]

try http://www.centertek.com

[another_jim]

try http://www.centertek.com

Oops!

Looks like the one I got is their top of the line, although several of their lower end models can accept J-types as well. They also have non-memory versions, which seems silly given the price of memory.