Hi, all,
I'm in the midst of productizing that cotton spark detector that I demoed in the spring, and talked about here a fair amount.
The architecture is a main control panel talking to N integrator units, each talking to 1 to 4 sensor units spaced around the periphery of a medium-large duct (30 cm to 1 m diameter). These detect sparks, but also measure window contamination and air velocity, to make sure that the sensitivity is OK and that the diverter door opens in time to catch the spark and dump it on the ground someplace safe.
The sensors talk to the integrator via Displayport cables, because of the very high signal integrity for the price.
I'm looking at ESD protection for the integrator-to-sensor links.
The analog signals are pretty slow, so 100 ohms in series and 1 uF to ground covers a lot of sins, like 20 kV HBM -> 2V on the cap.
There are digital lines too, though, which need to be somewhat faster than that.
The more capable general-purpose ESD protectors such as the SP720 are a bit on the pricy side for this, but I recall folks here talking about using the input protection networks on some jellybean logic family to do roughly the same job for a lot less dough.
What do you folks use?
Cheers
Phil Hobbs