sensorserial-busstandard
Following this question, @curious_cat had more questions in comments that deserve a proper Q here:
Is there any standard encoding that has evolved on the digital encoding side? Just as 4 to 20 mA is de facto standard on the analog side especially in process control?
So I wonder, in applications where rapid change is crucial, say airplane control, avionics etc. what sort of protocols have become the convention? Do they use 4 to 20 mA or PWM or dedicated buses?
I suggest you purchase / check out a copy of Henry Ott's "Noise Reduction Techniques in Electronic Systems". It talks about these things.
Don't ground the shield at both ends, as this creates a ground loop. The PCB end is probably the best place to ground the shield.
The best way to handle parts that don't appear on the schematic is to fix the schematic so that they appear. If you don't, you'll constantly be manually fixing the BOM that is automatically generated by your tools.
This applies to all the parts that belong to the immediate built board assembly. At the least, these are the parts that get soldered or otherwise mounted to the board. If the built board is part of a larger assembly, then the BOM for that assembly will show the built board as a single line item, and it can call out screws, nuts, standoffs, etc, for mounting the board into the larger unit.
And yes, this applies to sockets too. For example, here is a snippet of a larger schematic for a real commercial product that exists in the company's formal manufacturing database:
P11 is a Phoenix Contact connector that accepts a plug with screw terminals. Only P11 actually gets mounted to the board, but there always needs to be a plug with the board. That's what PLG2 is. It is there primarily for the purpose of automatically appearing on the BOM. In this case I think showing it on the schematic is also a nice visual reminder that the board comes with a screw-terminal plug.
Best Answer
In avionics (particularly flight safety critical) it is not unusual to see the usual comms (SPI, I2C) within a box, but externally it is usually going to be ARINC 429 (civil) or MIL-STD-1553B (Military) to / from sensors.
There are others such as STANAG 3910 which is used on Typhoon.
Within a system that communicates between boxes (not aircraft level) it is not unusual to see manchester encoded signalling.
I have also seen interfaces use HDLC / SDLC.
Oddly enough, the update rate for flight safety critical equipment is not that fast; typically 50Hz or so (put that in perspective for moving a flying control surface at a 20 milliseconds update rate)