Hello:

New here ... =-)

I would be very obliged if you'd allow me to tap into the collective
experience of this important group.

I need to connect a 4 wire PT100 immersion probe to a (very good
quality but now out of production) IR thermometer which has a male
socket like the one in the photo at the following link:

http://repairfaq.cis.upenn.edu/Misc/plug.jpg
(link hosting courtesy of SG at repairfaq)

I have not been able to ID it.

The inner diametre is ~ 5.5 mm.
It has what seem to be gold plated contacts and does not have an
orientation key, just push-on / pull-off with no threads or twist
mechanisms.

Being the socket for a PT100 probe, there's no special voltage
requirements, just negligible resistance.

Seems well made and the instrument it is on is of very good quality
and specs. eg: only Fluke ordinance and other similar quality + high
price IR thermometers/equipment have the posibility of variable
emissivity (E=epsilon) settings.

I doubt it is of a proprietary nature but you never know with some
OEMs.
They have not been very helpful.

The people at Omega haven't seen it before.
The tech guys at DigiKey and Mouser have been very diligent but don't
have it or know about it.

The instrument is European made, my guess is that the plug could also
be.

I'll be very grateful for any input.

Thanks in advance,
Best regards

CIV