DS2760 Recommended practice

Timothy D. Swieter

I am working on a project that uses the DS2760 Thermocouple kit. I am using a T-type thermocouple. The installation of the thermocouple into the chamber where I want the measurement has gone together well. The thermocouple wire is then run to the DS2760 which is in its own plastic case. According to the Parallax datasheet and app note the thermocouple wires should be striped and placed in the socket. Is there any reason to not solder them into the sockets on the PCB? My installation is permenant, so I want to ensure it is robust. This is my firs time working with them, so I wanted to make sure there wasn't a reason to solderin gthe wires into the socket.

Over in the Propeller forum I have been working on software for the DS2760 if anyone wants to jump in an give their advice from the software side. I am having trouble getting the calculations to line up in all conditions.

Propeller Software post: http://forums.parallax.com/forums/default.aspx?f=25&m=306775&p=1[noparse][[/noparse]url]

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Timothy D. Swieter, E.I.
www.brilldea.com - Prop Blade, LED Painter, RGB LEDs, uOLED-IOC, eProto fo SunSPOT, BitScope
www.tdswieter.com

Erik Friesen

I think it may have something to do with the different metals involved skewing the signal.

Paul Baker

I'm with Erik, themocouples operate on the marriage of dissimilar metals and produce voltage differentials in the uV (maybe up to mV) range. With these small values, creating other junctions could affect the voltage you're trying to measure.

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Paul Baker
Propeller Applications Engineer

Parallax, Inc.

Timothy D. Swieter

Thank you for the feedback. I understand marriage of dissimilar metals and can understand in theory how soldering could mess this up. I was also thinking that not having them soldered and just have them in the terminal may produce inconsistent results because of a poor connection. "In the real world" what is the means for making the thermocouple connection robust? Maybe it is a connector, but then you add the connection device plug the connection pins to the equation.

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Timothy D. Swieter, E.I.
www.brilldea.com - Prop Blade, LED Painter, RGB LEDs, uOLED-IOC, eProto fo SunSPOT, BitScope
www.tdswieter.com

Paul Baker

I would use a terminal block and screw it down tight. Still a junction, but a tight connection should minimize any loss.

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Paul Baker
Propeller Applications Engineer

Parallax, Inc.

Timothy D. Swieter

A terminal clock is a good idea. I will have to see if I can desolder the 2 pin IC type socket that is on the DS2760 kit and add a terminal block.

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Timothy D. Swieter, E.I.
www.brilldea.com - Prop Blade, LED Painter, RGB LEDs, uOLED-IOC, eProto fo SunSPOT, BitScope
www.tdswieter.com

stamptrol

Also available ( Omega Engineering, for one) are connectors with contacts made of the same materials as your t/c. Used to prevent the issue that Paul brought up.

Cheers,

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Tom Sisk

http://www.siskconsult.com
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