What is the simplest way to turn a regulated continuous analog DC +12 V (+/- 0.2 V) input signal into a 0 V output signal, and likewise turn a 0 V input signal into a +12V output signal?
Two separate sources are available for use, the first for driving the input signal at 12V+, or 0 V (when source is open circuited). The second for driving the output signal at 0 V (open circuit) or 12V+ nominal.
The first source is regulated to 12V +/- 0.2V or 0 V, the second source is unregulated 11.9 - 15 V.
The final detection circuit that will read the output signal considers 8.5V - 15V as a HIGH state. Anything below 8.5 V it registers as LOW.
Continuously-energized NC signal relays are undesirable due to duty cycle concerns (100% duty for months or even years), although some are rated for it and they may be the best solution. System is for safety purposes, so reliability is important.
I am looking for low power consumption, capable of withstanding -40°C to +85°C, reasonable amount of vibration tolerance, ideally a ready-made solution with minimal manual assembly and possible failure points.
Transistor inverter? Op amp comparator? Something else?