1 Topic by dubbsd

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Topic: using data logger to record temp.

Because I have had problems with the peek melting after PID tuning I am looking into adding a multi channel data logger to record temps. I would be able to keep an eye on the bed, nozzle, just below the peek, and enclosure temps all at the same time. Here are the data loggers I have been looking at. This way you can compare the the meter with Repetier-Host.

http://www.extech-online.com/index.php? … cts_id=408

http://www.omega.com/ppt/pptsc.asp?ref= … Nav=dase01

http://www.omega.com/googlebase/product … 4AodFzgA-Q

Ultimaker S3.

2 Reply by pcpoirier

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Re: using data logger to record temp.

You can slide the temperature graft back  to see the history on R/H

3 Reply by wilheldp

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Re: using data logger to record temp.

I'm actually building my own 8-channel, K-type thermocouple datalogger.  It's based on an Arduino, and all-told, the parts cost me about $150.

4 Reply by adrian (edited by adrian 2013-04-22 11:49:24)

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Re: using data logger to record temp.

wilheldp wrote:

I'm actually building my own 8-channel, K-type thermocouple datalogger.  It's based on an Arduino, and all-told, the parts cost me about $150.

The thermocouples themselves being the most expensive bit... the MAX31855's can be had for $3.50 from Digikey, and you just need a couple of caps to go with them.. But I'm still struggling to get to $150 BOM for only 8 Channels... Maybe $100 at a stretch if I went retail for the Thermocouples and included a genuine Arduino and not a clone... (but to be fair - I make PCB's and am very familiar with the MAX line... so perhaps not a good example...)

But in this scenario, unless you desperately distrusted the reported values, the built in temp logging would more than suffice.

5 Reply by Zarni

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Re: using data logger to record temp.

If you're looking for some thermocouples to monitor small items I suggest making them yourselves. Just get some thermocouple wire (not extension wire) and twist the ends together then put a blob of solder on just to hold it together.
This makes a simple bead thermocouple which I have made plenty of and work just fine. Just remember that any point where the two wires touch gives you the reading so if you bare too much wire by the chip end you end up reading room temperature., which I might have done a few time smile

Something like this http://uk.rs-online.com/web/p/thermocouples/6212158/ and then you can just cut them down to make loads of them for pennies.

It's only when you need them to fit in something like an exhaust manifold that a nice 6mm shroud is handy to make a gas tight fit.

6 Reply by adrian (edited by adrian 2013-04-22 12:29:12)

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Re: using data logger to record temp.

Hmm, completely OT now.. but if you can get chromel and alumel to wet and solder with standard stuff - you're doing better than me. I just capacitive discharge weld the buggers.... Not to mention that solder introduces another alloy into the mix and will distort the seebeck effect and therefore the entire accuracy of the thermocouple (but I'm anal about doing things properly, no point measuring cm's when you've got a ruler in inches eh?). I guess its ok for room tempreature etc.. prob even government work... but no good for something that you need accuracy on or rely upon for accuracy...

Anyway - I was more pointing out that any thermocouples are A: surperflous given Repetier-Hosts existing temp logging facilities and B: willheldp seems to have a very expensive BoM for a mere 8 channel temp data logger - even using 'retail' thermocouples...

Ah well - 'nuff from me now in here.. I've polluted the thread enough smile

7 Reply by IanJohnson

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Re: using data logger to record temp.

The RH graph is good, but only reads the bed and nozzle.  It would be interesting to see how the temps at the nozzle, heater and bottom of the PEEK track.

8 Reply by adrian (edited by adrian 2013-04-22 13:30:39)

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Re: using data logger to record temp.

IanJohnson wrote:

The RH graph is good, but only reads the bed and nozzle.  It would be interesting to see how the temps at the nozzle, heater and bottom of the PEEK track.


I'll drag out the Thermal Camera this week and shoot some footage for you when I get a moment - too busy with a 1001 other 'work' things next day or so...

9 Reply by wilheldp

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Re: using data logger to record temp.

adrian wrote:
wilheldp wrote:

I'm actually building my own 8-channel, K-type thermocouple datalogger.  It's based on an Arduino, and all-told, the parts cost me about $150.

The thermocouples themselves being the most expensive bit... the MAX31855's can be had for $3.50 from Digikey, and you just need a couple of caps to go with them.. But I'm still struggling to get to $150 BOM for only 8 Channels... Maybe $100 at a stretch if I went retail for the Thermocouples and included a genuine Arduino and not a clone... (but to be fair - I make PCB's and am very familiar with the MAX line... so perhaps not a good example...)

But in this scenario, unless you desperately distrusted the reported values, the built in temp logging would more than suffice.

That doesn't include the thermocouples, actually.  I got an Arduino shield from a company in Australia that includes screw terminals for 8 thermocouples, a signal amplifier, and a multiplexer.  Then I'm going to use the Adafruit datalogger shield (if they ever get any stock of them) to write the values to an Excel file on an SD card.  The package will also include a 4x20 LCD display and some control buttons.

10 Reply by adrian

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Re: using data logger to record temp.

wilheldp wrote:

That doesn't include the thermocouples, actually.  I got an Arduino shield from a company in Australia that includes screw terminals for 8 thermocouples, a signal amplifier, and a multiplexer.  Then I'm going to use the Adafruit datalogger shield (if they ever get any stock of them) to write the values to an Excel file on an SD card.  The package will also include a 4x20 LCD display and some control buttons.

Great stuff. Its always fun working with an LCD, sounds like a nice project. Be keen to see how it ends up!

11 Reply by wilheldp

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Re: using data logger to record temp.

I'll make a thread about it when I get all the pieces and really start working on the code.  If I forget, kick me if you see me post about something else.  I have the attention span of a...

12 Reply by Zarni

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Re: using data logger to record temp.

Sorry for the confusion earlier, any solder is just a blob to stop the wires coming apart, without it they tend to undo themselves. The bit of solder doesn't seem to affect accuracy as there is always a point where the two wires touch closer to the chip that didn't have solder on. Good for a couple of hundred degrees C before the solder melts but if held still will work happily up to 1100c, but by then everything is glowing white hot smile
As for sensor accuracy from making your own thermocouples we found 0.1c was good enough for what we needed.


I'm now really interested to see the images from your FLIR camera. I've wanted to buy one for years but could never justify the costs.
It could highlight where work on the thermal break needs to focus and what sort of temps we are running including the extruder motor which I have been curious about.