I want to ask, is there any application of the fault tolerance ability in microcontroller? I was a bit confused, will there be any fault when the microcontroller perform something if the input is right? if there is, what is the example of it?
Sorry if the question is dumb.
What is the application of fault tolerance system in microcontroller
faultmicrocontroller
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That's a decent way to do it, but I'd use a bipolar transistor such as a 2N3904 or 2N4401 (MMBT3904/MMBT4401 in SMT). Yes, you need one or two more resistors, but they're more immune to surges. The IRLZ24N can be damaged if you put more than 16V on the gate.
It's also gross overkill for the job, and is not guaranteed not to leak enough to overcome a typical weak pullup in an MCU, especially at elevated temperature. If you insist on using a MOSFET, a 2N7000 with a resistor and zener on the gate is more appropriate (2N7002 in SMT).
In many cases you could just use the 9V and pass it through a resistor + Schottky (BAT54) clamp to Vdd and read it directly (turn the pull-up off). The resistor could be relatively high value like 100K.
simulate this circuit – Schematic created using CircuitLab
This assumes you're only looking for a go/no-go indication of the presence of some voltage on the analog power supply. If you want to know when it is within spec, you'd need to use a comparator (maybe your MCU has one on-board- many PICs do). In such a case, and lets say the internal comparator reference is 1.024V, you could divide down the 9V so that it gives you 1.137V at 9V in, so that the comparator changes state at about 8.1V on the analog supply (when it is at nominal less 10%). Alternatively, you could use an on-board ADC channel and do the comparison digitally.
The device measures the current flowing between the screw terminals, which are isolated from everything else. the pins are to power the hall effect sensor only, however, there's no reason you couldn't have power going through the screw terminals and then going to anything you want, those screw terminals are isolated from the pins so measuring itself is fine. Although those hall sensors aren't known for having amazingly good sensitivity, if you've got a 5A sensor, you'd be hard pressed to measure with an accuracy (or resolution) of much better than 50mA.
Best Answer
Fault tolerance is important in situations where failure is not an option. It's not limited to making sure inputs are correct, but also that your current state does not spontaneously change.
For example, how sure do you want to be that your bank account doesn't spontaneously change value? Or the software controlling the plane you're riding in always working?
One of the more common fault tolerance devices is Error Correction Code memory. This protects against random bit flips which can happen in DRAM due to external effects such as radiation. As an extreme case, the Wiki article claims that the deep space satellite Cassini suffers on average 280 errors a day! It would be extremely poor planning if you lost a multi-billion dollar project due to any single one of these.
Another common case for fault tolerance is protection against (some) software bugs. There might be some rare situations where the software gets stuck in an infinite loop. In these cases a watchdog timer can be used to ensure that if this happens, then a soft reset is forced to try and recover from this fault case.
Fault tolerance is also being researched for application in extremely low power electronics. When transistors are run at very low voltages, they have an increased chance of not operating as intended. One idea is if your chip is able to deal with faults when they happen, you can take advantage of the power savings when things go right, and only pay the higher power cost when a fault occurs.