2 .The hardware realizes the main point
2.1 Restored to the throne regularly unconditionally
Generally have 2 kinds of methods. ① Use theitimer or the special-purpose
clock chip to be restored to the throne. Fig1, in order to use the timing circuit
that 555 circuit makes up; Can use the clock chips of X1126 ,etc too , wake
CPU up with the alarm signal after setting up warning time. This kind of method
is suitable when the long interval is made, can also follow the result of this
operation ,determine to wake time up in alarm next time temporarily, very
flexible and convenient. ② The signal of using the system to be inherent is
as reducing the pulse regularly. Use 50Hz worker power make reducing after
having a facelift frequently, already omit the timer, gathered the
corresponding signal for the phase place which measured the electric current
signal at the same time, as Fig. 2 shows.
2.2 External conditions are restored to the throne
Send external condition pulse to and is restored to the throne the end son
after having a facelift. To that above-mentioned water wheels or the ammeter
spend a pulse produced, can use Schmitt's trigger to have a facelift; For writing
down the instrument of the biggest or minimum,can use the window
comparator. In order to realize the electronization that is regulated,can use
the electronic electric potential device, establish upper and lower limits with
the order of the one-chip computer.
2.3 Reduce cycle and restored to the throne the high electricity at ordinary
times