Good Deal on Dual Temperature Digital Datalogger

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plexus
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#1: Post by plexus »

I had been looking for one of these on ebay. I kept checking and tonight i saw this listed at $30-50 less than they usually sell. so i bought one. $99 plus shipping!

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0312364913


UEi APOLLO II DT302 Digital Temperature Logger

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JohnB.
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#2: Post by JohnB. »

Let us know how accurate it is after you calibrate it. I'm looking for one & don't really want to spend the $$ on a Fluke.
LMWDP 267

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JB130
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#3: Post by JB130 »

Wow, does look like a good deal! Thanks for sharing. Is the USB cable and downloading software extra, or does it come with it? It's not clear from the datasheet and listing.

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farmroast
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#4: Post by farmroast »

I bought the DT304. It will constant display 2 readings on the hand monitor. They had a rebate offer up til jan1. It works well but the software could be better but is workable. The Flukes are a lot more expensive.
farm
edit mine did come with the software and usb cable
LMWDP #167 "with coffee we create with wine we celebrate"

decaf_Ed
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#5: Post by decaf_Ed »

Measurement Computing has a device (under $100, ships with a massive K-type probe) that is easy to use with no extra expenses, other than a low-mass T-type thermocouple. It only has a single channel, and max speed is 1 sample per second, but it does take T-type (and K and J).
An Omega 30-gauge beaded T/C is shown below, who's connector is the blue thing on the left. USB port is on the right, plugs in like a thumb drive (generally not plugged in while logging, but maybe it could be).
-Ed

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GVDub
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#6: Post by GVDub »

decaf_Ed wrote:Measurement Computing has a device (under $100, ships with a massive K-type probe) that is easy to use with no extra expenses, other than a low-mass T-type thermocouple. It only has a single channel, and max speed is 1 sample per second, but it does take T-type (and K and J).
An Omega 30-gauge beaded T/C is shown below, who's connector is the blue thing on the left. USB port is on the right, plugs in like a thumb drive (generally not plugged in while logging, but maybe it could be).
-Ed
If that thing outputs data while it's logging, the geek part of me wants to mate it (or a few of 'em) with something like a mini-ATX running some *nix off an SSD attached to a 5" touchscreen and start building the espresso-puter. Open Source Espresso (and not the web development platform). Take a lever machine, add some servos and pressure sensors and you could come up with some real pressure profiling. Switch to a induction system to heat the boiler rather than a resistance element, and you can get finer temp control with direct microprocessor control. Heck, hook up a web cam and some server software and make the whole thing live on teh intarwebs.

Jeez. Maybe I better cut back on the caffeine a little, huh?
"Experience is a comb nature gives us after we are bald."
Chinese Proverb
LMWDP#238

decaf_Ed
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#7: Post by decaf_Ed »

That USB-510-TC model won't feed through in real time (without some serious hacking). But if you wanted more than one channel, and feedthru instead of logging, maybe this one will do it:
http://www.measurementcomputing.com/usb ... SB-TC.aspx
-Ed

EricL
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#8: Post by EricL »

farmroast wrote:I bought the DT304. It will constant display 2 readings on the hand monitor. They had a rebate offer up til jan1. It works well but the software could be better but is workable. The Flukes are a lot more expensive.
When you get it up and running, could you post a mini reveiw. What kind of sample rates does it support, and how many samples per channel?

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farmroast
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#9: Post by farmroast »

Intervals can be set from 1sec. on up by the sec.. Saves in .csv or .txt. I use it on my roaster for BT and ET
LMWDP #167 "with coffee we create with wine we celebrate"

plexus (original poster)
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#10: Post by plexus (original poster) »

I have been experimenting with the DT302 and am ready to share my experiences. In brief, its a great little logging temperature meter and is well suited to my home roasting needs. One caveat: i am a "good enough" kind of person and with temperature monitoring and logging, I am not so interested in absolute accuracy. As long as its "close enough" im happy. so if its out by a couple degrees thats fine. Frankly, I cant control the temperature that fine anyway in my Hottop B. So with that in mind...

Mini Review of the Uei DT302 Apollo Dual Channel Temperature Meter Datalogger

The DT302 features 2 thermocouple (TC) inputs, a large primary display, a smaller secondary display for temperature, a display for time and other typical display toggles (unit, TC type, mode etc). It has an internal TC to monitor ambient temp. The most used mode is to have T1 in the primary display, reading bean mass temp (BT) and T2 in the secondary display reading roaster environmental temp (ET). You can easily toggle the primary display to T1-T2 in which case T1 will be in the secondary display, by pressing the T1/T1 button. Holding this button places the internal ambient temp in the secondary display.

The time display can be set to show hh:mm or mm:ss in the setup menu. in the former you wont see the seconds counting and in the latter you wont see the hour. for my use, i have it set to mm:ss so i can make hand written notes based on the time shown in the display, to the second. the time display is real-time and the time and date are set in the setup menus.

The meter has a pretty fast sampling rate of about 2-3 times per second for each channel. so you get a pretty good reflection of the temp. unlike the hottop ET monitor itself which seems to sample every 2 seconds or perhaps every change of 2 degrees. so, faster sampling with the DT302 in the display.

The primary display is actually quite large and easily readable. the display contrast is high and is crisp. there is a toggled backlight if you need it. the backlight will go out after a few minutes so you have to keep toggling it on if you want that feature. its not a backlight either, rather its 4 yellow leds around the display so the quality of the backlight isnt so good. but if its dark its better than nothing.

physically the meter is a little bulky with the protective shield around it. i took that off and it made the meter pretty sleek. there are storage areas under the meter to hold the included TC's flush inside the case which is nice. i am not using the stock TCs, rather i am using 2 others i got with another meter simply because thats what i have been using. the ones that came with it will be spares. i am using type K.

Once you go through the setup menu and set all your settings, which are not too bad for a chinese made meter, you can get to business. what i mean is that the settings arent totally cryptic as they can be in some of these kinds of things and they arent too difficult to set. not perfect, but not bad. after you have your settings in, you can get to measuring.

My T1 probe is in the front of the HT in the sight glass where the beans accumulate on the window. My ET is set in the back through the chute, on the far side of the drum from the heating element. I frankly dont really care about ET as much as I do BT but since i have to channels, why not. Eventually i will make a more permanent set up with the TC's in the HT once i have time.

To start logging you first have to clear the log memory. If you dont, your logging will be appended to whatever is in memory. You could use this, perhaps, to store multiple roast logs. there are 9999 memory locations, so if you log every second and a roast is on average 20 mins, you could store about 8 roasts in the memory, one after the other. visually they would be delimited by the drop in temp. so this could be done. i choose to clear the memory and start from scratch at each roast. to clear the memory you hold the log button until it asked you to clear and then you keep holding it down until it askes you to confirm and then hit enter. cleared. then to go into logging you press the log button quickly and the LOG display lights up. the meter is now logging.

there are preset log intervals of 1s, 10s, etc etc. but you can set the interval to be whatever you want (within in some limits). i like 1s logging but 10s logging might be all you need. you do your roast, and when you are done, turn off logging and thats in. time to interface to the computer and look at it.

the software comes with the meter. its on a small cdrom, called DT300 Logging software. the DT302 has a 1/8" minijack on the front and comes with a cable that terminates in a USB jack. i found i had to wiggle/push hard on the jack into the meter to get it to go in all the way, a sign of a cheap female internal jack. oh well. the software installation is pretty fast and its not a large application at all. its pretty easy to use.

now, i am on a mac. i was really hoping i could use this meter with my mac with windows running under parallels. parallels is a mac app that lets you run windows and windows apps at the same time as the mac os. my set up was with windows 2000. this did not work. when i plugged in the meter, windoze went into found new hardware and tried to install a com port. this hung windoze. so i opted to use my desktop pc. same process but this worked. to make a long story short, i got it to work on my mac by installing xp. maybe a fresh w2k install would work. i'll tell you later why i wanted to get this working on my laptop.

but for the first few roasts i used my desktop pc connected to my wireless network to get the data off the meter. the meter uses a serial interface interally. i think maybe early ones had rs232 output. there is a chip in there that bridges the serial interface to usb called the cdc rs232 usb demo. so its a bit of a kludge to get this to work with usb. but on the outside world all that matters is that it does work.

the software comes up and and if you have the meter connected, on and its interfaced to the computer ok, the status at the bottom will tell you so. at this point you can download the log data off the meter by selecting download from one of the menus. the data comes off and you are presented with a graph of T1, T2, T1-T2 and time along the x axis. the graph auto-scales to fit the X and Y data limits. you can select to turn off T1, T2 and/or T1-T2 to show whatever you want. the time scale is in real time showing the full time and date. the graph includes an x and y axis grid. which makes it easy to read off the data.

i didnt fiddle too much with graph settings so i am not sure if you can specify fixed scales, change the colours of the lines etc. i dont think you can. thats fine. you can save out the data in text or csv format. both formats save out the the same data just formatted differently in the file. here is the top portion of the csv file, re-formatted as text (eg. the commas have been turned into tabs):
Title Logged Data
Date/Time From : 2009/03/24 15:32:26 To : 2009/03/24 15:59:40
Model DT302
Interval 00:00:01
Unit ∞F
ThType K
Sample Points 1635


Func./Ch. T1 T2 T1-T2
MAX Index 1598 387 1583
MAX Data 428.7 486.3 -23.0
MIN Index 1 1 392
MIN Data 105.9 140.4 -206.8
AVG Count 1635 1635 1635
AVG Data 318.3 373.3 -87.7

No Date Time Set T1 T2 T1-T2 Unit
1 2009/03/24 15:32:26 72.6 105.9 140.4 -34.5 ∞F
2 2009/03/24 15:32:27 72.6 106.2 140.7 -34.5 ∞F
3 2009/03/24 15:32:28 72.6 106.8 142.2 -35.4 ∞F
as you can see there are is some useful data here. you can bring this into a spreadsheet app and build your own charts with it. here is an example of the chart that the logging software creates. this is a screen shot from the app:



this was captured at 1s intervals and does not include T1-T2. the green line is T2 or ET and the red line is T1 or BT. for this roast i dropped the beans in when the ET was around 320F as can be seen by the drop in temp. at 1/2 through drying i dropped the heating element from 10 to 6 for the duration of the roast (which i think lengthened it too long but thats another story).

As you can see this really helps to visualize one's roast. you can make notes as you roast based on the real time display and then transcribe these onto the chart. here is an example:



I didnt bother to try and re-create the chart using a spreadsheet app. frankly apple's keynote chokes on all those data points when trying to make a graph so i decided not to bother. excel would work better but i couldnt be bothered because i got what i needed from the Uei DT300 software.

now the cool part: the software allows you to chart in real time (!!). you can connect the meter, press the play button in the software and the software will sample the meter in real time and create a graph for you as you go. this is why i wanted to get the macbook working with it, so i could bring the macbook to the roaster and WATCH my roast as i roast. i just got this working last night with XP under parallels so i havent tried a roast yet, but this will let you watch your temp in the form of a graph in real time so you can make more deliberate adjustments. once your log, you can save out the data as normal. the software also features a "virtual meter" which is the meter as a graphic on your monitor, with the display showing in real time what the actual meter shows and the buttons working the same way. unfortunately you cant seem to have the virtual meter open at the same time you are graphing.

I bought the meter brand new off an ebay seller for $99US. after shipping and exchange it came to $166 canadian. over-all a very good price on a good, totally functional for home roasting, 2 channel data logging meter which includes k type TCs and software.

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