multi-channel analog to digital converter - for control computers

for control computers The use of a microprocessor system as control computer often makes it necessary for a large number of analog signals to be monitored. If a certain degree of accuracy is ex- pected from these signals, a number multi-channel analog-to-digital converter //% // of suitable A/D converters will be needed. And that is not exactly cheap . . . The circuit presented here offers the facility of connecting eight analog signals to a CD 4051 multiplexer. The channel select inputs, A, B, and C, select the signal being monitored at the time: at binary 000, channel ANO; at binary 001, channel AN1; at binary 010, channel AN2; and so on. The selected analog signal (which must lie between 0 and +5 V) is passed straight through to the output (pin 3) of the CD 4051. The channel select inputs may be controlled by, for ex- ample, three lines from port B of a peripheral interface adapter (PIA). The actual A/D conversion is carried out by a CMOS IC type ADC804. This transforms the ana...