For the internal plumbing system of a rocket which is expected to reach 100 km above the ground, industrial pressure sensors with a 4-20 mA current output and a 0-10 VDC output are available. What would be a more reliable choice?
As far as signal integrity, 4-20mA is almost always better. Two reasons why:
- Noise is usually less of an issue.
- Circuit discontinuity is instantly detected.
As for its use in high g applications, that is more up to the sensor itself, both electrical and mechanical construction. Note if it is more then just a sounding rocket, i.e. entering LEO, then you need to start considering radiation from the environment as well and it's effect on the electronics.
There are several situations where choice of 4-20mA current is necessary
a) Where the receiver already exists and is 4-20mA
b) Where you need to transmit over a substantial distance of wiring
c) Where there are particularly high levels of EMI
Other than those, you have a fairly free choice. The reliability of the sensor and the control electronics themselves will be similar, especially if made by the same vendor.
Most people find it easier to design around a voltage interface, and you may well use fewer components doing it. In which case you'll least chance of messing it up going the 'easier' route of a voltage interface.
Bear in mind that in electronic design, getting an interface to do what you want when everything else is behaving as you expect is the easy bit. Anticipating what can go wrong, and handling it without causing other things to blow up, that's the hard bit. With a rocket, you usually only get one chance to test it live, so figuring out how to test it adequately before flight ought to consume >90% of your research.
I assisted very senior engineers in producing 6" BY 6" BY 4" HIGH black telemetry boxes for TRW. In assisting them, I had the opportunity to examine the schematics.
The inputs were:
....high-level analog single-ended,
....low-level analog differential-ended into amplifiers
....and digital switch-closures (logic levels)
MOSFETS (tho sometimes special-doped bipolars) were used as the analog multiplexors.
Analog Digital Converters, using 0.01% red-cased wirewound resistors in R-2R-4R-8R etc DAC structures, using the UA710 single comparator, were the state-of-art and extremely reliable. [I'd written UA711, but was 710]
These small telemetry systems had to, after being conformal coated against fungus, sit in storage at Cape Canaveral for 25 years without failing, then be launched in extreme vibration and shock, and then perform for 25 years in orbit --- all sorts of particles impinging on the circuits to degrade current gain and degrade junction leakage. Glass sealed tantalums were the favored large-value capacitors; glass capacitors used in precision timing.