Electronic – PCB Edge to Edge Connectors

The most important part of how/where/when for connecting a thermocouple is to measure the temperature as close as possible to the bimetalic joint.

From here feed that temperature into your uP and then you can use software to perform the CJC compensation and use the known polynomials (or simplified linearised equation for smaller ranges) for converting your ADC value into temperature.

In the past we have got a big chunk of aluminium and performed wire to wire terminations around it and installed a LM35 for temperature measurement. This was performed off the PCB.

Having said that you can freely do it with connections n stuff on the PCB as long as for are able to measure the temperature as close as possible to the bimetalic junction.

So to keep the distance as short as possible consider using screw terminals and mount the LM35 right near the screw terminals themselves for the most accurate reading. If you really want to use a connector try DB9 with the metal back shell - cheap as chips and being metal will conduct heat well for accurate measurement of the back shell temperature. Use male pins on the PCB.

I assumed you are using a uP and software, if not you can do the CJC in hardware but thats a bit trickier.

Hope this helps.

If this is for production access only, then here's a trick I used once. The PCB (standard 0.062" thickness) was designed with SMT pads along one edge (both sides) so that a 2×7 0.100" JTAG header could be soldered to it, with the pins sticking out from the edge. This was useful for debugging prototypes, which needed more or less constant access to the JTAG (and weren't in cases).

In production, the connector is omitted, and I used a slightly modified DIP clip to access the pads for the connector. I just needed to bend the contacts inward a bit to get adequate friction and contact pressure.

Instead of the DIP clip, you could use a standard card edge connector as well.