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Note from Marc:
The only CBP-specific advice that I can add is to pay attention to when and how the instruments update their lines. For example, the keithley trigger-out line is normally high and goes down when the measurement complete. The other instruments were behaving in the opposite way. This is why we monitor by default the falling edge on line 2 and the rising edge on line 0 and 1. Also, we never completely figured out the exact timing of the two pulses of the keysight, we assume they correspond to the beginning of the first sample and the beginning of the last. It seems to work but that may be off by one integration period (which is small for the keysight).
Link to his setup: https://github.com/betoule/logic_timer
Sparkfun non-inverting optoisolator board is BOB 09118, two channels of logic per board.
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