Thermocouple wiring to GPIO board?
Posted: Mon Apr 09, 2012 10:02 am
Question: What are the various connectors to properly wire thermocouples (EGTs) to the GPIO case/board?
Background/Discussion:
I intend to use the 4 dedicated EGT circuits on the GPIO. I understand the importance of properly wiring thermouples to avoid adding additional junctions to the circuit as explained in the manual, http://www.msgpio.com/manuals/egt.htm , specficially,
As I understand it, running the thermocouple leads through the AMPSEAL connection would be undesirable because it would add additional junctions. The ideal situation would be to have the thermocouples soldered directly to the board which could make installation and EGT sensor replacement/troubleshooting difficult. Also it could be difficult to properly seal the wiring.
For my installation I would like to use thermocouple connectors so the thermocouples are easily removable. I have come up with two solutions.
The first is to use a bulkhead (or panel mount or panel jack) connector that could be installed on the opposite end of the GPIO case as the AMPSEAL. As an example I think the Omega MPJ-K-F may work well (http://www.omega.com/Temperature/pdf/MPJ.pdf). However I'm not familiar enough with these to know how well they seal.
The second is to use a high density wiring feed-through to pass the extension wire through the GPIO case on the opposite end of the AMPSEAL and then use a standard thermocouple connector outside of the GPIO. I'm sure there are several manufactures, but I'm most familiar with Conax. Something like their high density multiple wire feedthrough comes to mind, as shown in the second photo down on page 37 here, (http://www.conaxtechnologies.com/produc ... _5001C.pdf ) where the left side would be the inside of the GPIO case and the right side with the connectors would be outside the GPIO.
I think I prefer the bulkhead connector personally as it would avoid having dangling wires coming from the case, but would like to get other opinions on the matter.
-Troy
Background/Discussion:
I intend to use the 4 dedicated EGT circuits on the GPIO. I understand the importance of properly wiring thermouples to avoid adding additional junctions to the circuit as explained in the manual, http://www.msgpio.com/manuals/egt.htm , specficially,
.The thermocouple leads must continue all the way to the PCB pads on the GPIO main board. "a" on the GPIO EGTx circuits board for alumel, "c" is for chromel. The thermocouple leads should be silver soldered to those locations. You can use connectors (to allow the thermocouple to be detached from the GPIO), but these should be dedicated thermocouple connectors (which are made of alumel and chromel) otherwise you will introduce a second junction, and the readings will be inaccurate
As I understand it, running the thermocouple leads through the AMPSEAL connection would be undesirable because it would add additional junctions. The ideal situation would be to have the thermocouples soldered directly to the board which could make installation and EGT sensor replacement/troubleshooting difficult. Also it could be difficult to properly seal the wiring.
For my installation I would like to use thermocouple connectors so the thermocouples are easily removable. I have come up with two solutions.
The first is to use a bulkhead (or panel mount or panel jack) connector that could be installed on the opposite end of the GPIO case as the AMPSEAL. As an example I think the Omega MPJ-K-F may work well (http://www.omega.com/Temperature/pdf/MPJ.pdf). However I'm not familiar enough with these to know how well they seal.
The second is to use a high density wiring feed-through to pass the extension wire through the GPIO case on the opposite end of the AMPSEAL and then use a standard thermocouple connector outside of the GPIO. I'm sure there are several manufactures, but I'm most familiar with Conax. Something like their high density multiple wire feedthrough comes to mind, as shown in the second photo down on page 37 here, (http://www.conaxtechnologies.com/produc ... _5001C.pdf ) where the left side would be the inside of the GPIO case and the right side with the connectors would be outside the GPIO.
I think I prefer the bulkhead connector personally as it would avoid having dangling wires coming from the case, but would like to get other opinions on the matter.
-Troy