Supervised input converter
View Patent ↗A multiplexer selects an input signal from one of plural sensors. An A/D converter converts the selected input signal to a digital input value. A processor then determines, based on the digital input value, an output resistance to which the resistance of the selected sensor is to be translated. Finally, the processor controls a digital potentiometer corresponding to the selected sensor to the determined output resistance. In one embodiment, a conditioning circuit adjusts the gain of the input signal according to calibration data, effectively performing at least a part of the translation in the analog domain.
1. A supervisory input converter, comprising:
a processor;
a multiplexer for selecting, under control of the processor, an input signal from one of plural sensors;
a conditioning circuit which adjusts gain of the input signal;
an analog-to-digital converter which converts the selected input signal to a digital input value, the processor then determining, based on the digital input value, an output resistance to which the resistance of the selected sensor is to be translated; and
a digital potentiometer corresponding to the selected sensor, the processor controlling the digital potentiometer to the determined output resistance.
2. The supervisory input converter of claim 1 , further comprising:
at least one lamp providing a status indication.
3. The supervisory input converter of claim 1 , further comprising:
non-volatile memory which holds calibration data.
4. The supervisory input converter of claim 1 , further comprising:
a serial interface.
5. A method for converting supervised input signals, comprising:
selecting from a plurality of supervised inputs, each supervised input having a corresponding input resistance indicative of said supervised input's state;
adjusting gain of a signal from the selected supervised input signal, said signal prior to adjustment being indicative of said supervised input's resistance;
converting the selected supervised input's input resistance to a digital input value; and
controlling a digital potentiometer to a desired output resistance responsive to the digital input value.
6. An apparatus for converting supervised input signals, comprising:
means for selecting from a plurality of supervised inputs, each supervised input having a corresponding input resistance indicative of said supervised input's state;
means for converting the selected supervised input's input resistance to a digital input value;
means for adjusting gain of a signal from the selected supervised input signal, said signal prior to adjustment being indicative of said supervised input's resistance; and
means for controlling a digital potentiometer to a desired output resistance responsive to the digital input value.