Hi folks,

Things are going very well with the artisan software and before Christmas I am planning to have the release of the first beta version (I have time). The goal now is to make it compatible with any roaster by using an affordable interface (dual meter RS232) so that it can also be use/tested by other people. With a meter, it cannot control the temperature of the roaster (with a PID yes). It could only record and plot data. A good affordable candidate is this one:

http://www.omega.com/pptst/HH506A_HH506RA.html

which looks very similar o this other one (they may use the same manufacturer but different brand):

http://www.extech.com/instruments/produ...prodid=410

I think they can take a power adapter to leave always on (better without batteries).

Does anybody knows of a better candidate before I press the trigger on one of the above choices? The requirement for the device is that it needs at least two channels (BT and ET thermocouples), have RS232 port and have a reasonable price.

Cheers

PS

Screenshot

I'm not 100% certain, but I think these devices power the CJC from the battery.
When the battery gets low, readings go haywire, even when powered from a bench supply.

Other than that, they're quite nice.

Arpi wrote:Does anybody knows of a better candidate before I press the trigger on one of the above choices? The requirement for the device is that it needs at least two channels (BT and ET thermocouples), have RS232 port and have a reasonable price.

I don't know if it is a "better" candidate, but a group at Homeroasters.org has been working on a DIY device that matches your description:
http://www.homeroasters.org/php/forum/v...rowstart=0

More info, including software and hardware schematics (open source) here:
http://code.google.com/p/tc4-shield/

Output from the device consists of a CSV data stream (1 Hz sample rate) over a USB COM interface.

Jim

EDIT - I guess I should mention that this is a not-for-profit project.

I've got the Omega meter you linked; it is a nice meter for the price and the company that sells it (Omega.com) was great to order from when I purchased. The 12 dollar storage case is a nice addition and fits the meter well. I don't think there is an AC power option though so if that is something you want/need, check into it carefully - I sure don't see any connection on my meter for AC power.

I use this low cost four channel one by Centertech. It uses Type K only, and only goes as fast as 30 readings per minute; but has been very reliable. It also has nice software. You do need to add the RS232 to USB converter. However, Omega now sells a four channel job with a direct USB connection for $300, so that may be the better deal.

Two channels, bean and environment, is fine once the roaster is operational; but three or four channels makes it much easier, on a new or modified roaster, to find the best monitoring points by directly comparing two alternate sites for bean or environment and seeing how they relate (or fail to relate) to the other sensor.

Thanks.

I think I'll go with Omega (looks like the most popular). Hope they use the same protocol form for several of their meters. That way I could kill several birds at one time. I've notice that with Extech they have the same software for different meters which would mean that they use the same type of protocol.

Cheers

Hi again.

I just thought that I could also import files (ie. cvs files; not in real time) from any meter (after being loaded to a PC) even when the meter is not RS232. That way, you could plot profiles and compare them with any other roaster (superimpose). I'll try to make it as universal as possible. I would need to get a hold of one of the files for each meter.

As far as making RS232 meters compatible with the software (for real time plotting where you can use the buttons to mark the roast), I would need to get a hold of each meter and its software for a couple of days.

Cheers

Rafael -

The Extech meter, at one time and POSSIBLY still today, had the ability to operate from a transformed 120 vac power source. The Omega HH506RA, while essentially an identical meter, has never had that capability. The Omega HH806 series offers that 120 vac power source - http://www.omega.com/ppt/pptsc.asp?ref=HH806&Nav=teml04 for a little more $.

I do believe you want a meter that can connect to a pc via a USB port. That's extra with the 506RA, standard with the 806 series, and (I don't think) available with the Extech. The typical protocol is for the meter's software to import the data to one's pc in CSV format. I could send you the raw CSV file from the Omega 506RA if that would help.

Thanks Eric.

If the meter uses a serial to usb chip then it could be possible. But then I won't be able to look at the communications data and I won't be able to see the commands/format they use. It is possible but much more difficult, outside the scope of my willing time to spend.

Send me the file (of two thermocouple readings) to take a peek.

Thanks

It's possible to use Portmon for Windows v3.02 to examine and capture a COMM stream.

Some devices require a specific timing on commands. I've seen some devices remain mute until suitable delays are inserted in the command stream.