There was a short circuit in one of the furnace that I designed.
Description of the furnace and its components: The furnace is a copper tube, with 1/2 inch thickness, and 10 equally spaced 1/4 inch bores for inserting the heaters and thermocouples.
I'm controlling the heating of the furnace with the following controllers:
The working of the heaters are controlled by the solid state relays and they are in turn controlled by the 16-output relay. The VINT hub is used to connect the 16-output relay to the computer so I can control them with LabVIEW. There are 10 heaters in total and each heater current consumption is 3A. I used two separate outlets to power 5 heaters each as the power outlet rating is only 20A in total.
Circuit diagram: I apologize for the clumsy circuit diagram, it has been quite some time since I did circuit diagrams and as of now my diagrams quite clumsy.
Description: The DC source is for controlling the solid state relays and goes through the 16-output relay. The AC source is for the heaters,not shown in diagram, the connector HTC2F is the connector which connects to all the heaters. All HTXL's are the solid state relays.
I have made a LabVIEW program where I monitor the reading from the thermocouples and control the 16-output relay for switching the heaters on and off through the solid state relays.
The incident: I was running the LabVIEW program to heat the furnace, but I accidentally ran a previous version I wrote which does not switch off the heaters when the desired temperature is reached. I initially plugged in one outlet and 5 heaters started heating up, and when I switched on the other outlet after a few seconds I heard a pop sound from the furnace and there was short circuit. The phidgets (VINT and the 16-ouput relay) burned. It also burned my computer mother board.
Need help with: Now I'm not sure how to test the system to check which heaters and thermocouples failed and replace them. Quite honestly I'm afraid to control them with LabVIEW as I'm afraid of the short circuit ruining my computer and the phidgets again. Any troubleshooting tips are appreciated. If there are any design flaws please let me know and I'll work on them.
Please let me know if any additional information is needed, I'll update the post with additional information.