US 4,234,870 A · Vital electronic code generator

Abstract

A code generator including a programmed microprocessor for transmitting a selected fixed frequenccy signal through optical isolators to tuned vital relay drivers. Feedback information from these drivers monitors their operation and checks operation of output circuitry. External time delays are provided to check program delays within the system and to ensure against the generation of erroneous codes due to cyclical resetting of the system. A rate selector is provided to permit selection of particular output code rates and is cycle checked continuously to ensure that the system is always certain of the selected code. Unique programming functions are also provided for self checking and for checking the operation of the microprocessor against the operation of external components to provide total system integrity and total system reliability. Diversity and cycle checking are used throughout the system to provide vital qualities. The system has no failure bias and is entirely self checking. Any component or program failure or malfunction causes the system to shut down completely.

Claims15

Dependent claims

A vital electronic code generator comprising:

a programmable central processing unit, said central processing including means for generating a signal at a selected code rate, said signal including pulses formed by a carrier signal of a given frequency,
relay driving means for operating relay contacts, said relay driving means including circuit means tuned to said frequency of said carrier signal for discriminating against signals of other frequencies,
output channel means for coupling said relay driving means to said central processing unit;
and,
feedback means coupled between said relay driving means and said central processing unit for comparing the activity of said relay driving means with the output of said central processing unit.

2 more elements

A self checking fail-safe electronic code generating network comprising:

signal generating means for producing carrier frequency signal and a selected output code rate,
tuned circuit means coupled to said signal generating means and tuned to a particular frequency for transmitting only signals having said carrier frequency,
feedback circuit means coupled between said tuned circuit means and said signal generating means for stopping said signal generating means if the frequency of said carrier signal drifts from the frequency to which said tuned circuit means is tuned.

Dependencies are inferred from the claim text.

Vital electronic code generator

Life of this patent

Vital electronic code generator

Life of this patent

Abstract

Claims15