I am building a setup to measure various parameters across a temperature range from -55°C to +125°C. The devices under test will be placed in a climate chamber. There are around 10 signals from each DUT to be measured by equipment outside the chamber. The sampling rate is fairly relaxed (many seconds). Measurements are DC (so no high speed signal issues). Switched voltages are below 12V.
I plan to have around 50 DUTs in the chamber. Only one DUT has to be connected to the measurement equipment at a time.
I wonder what is an efficient and reliable way to mux ~500 signal to and from a climate chamber?
Some solutions that I considered:
Switching signals outside the chamber - physically impossible, 500 wires will not fit through the conduit (and it would be a mess of wires...).
Switching inside the chamber using ordinary relays - may not be reliable
Switching inside the chamber using relays rated for such environment - horribly expensive
Switching inside the chamber using solid state devices - may have unpredictable effect on the measured signals