Design of intelligent manual operator
Liying Wang · 2006
The hardware composition and main software design of the manual operator are introduced entirely.The manual operator is a supporting instrument which achieves manual operation in a control system.It is demanded for a manual operator to realize bumpless change-over.The key technique of manual operator design is how to change over between manual-operation and auto-operation without excitation.It is devised for ICL7135 interfaced with microcontroller 89s51——shared one crystal oscillator,which A/D converting value is obtained indirectly through T1,so that A/D conversion precision is enhanced greatly.The instrument precision depends mainly on bit amount of D/A converter.The range adjustment and zero-point adjustment of the metre are both realized in D/A conversion circuitry.The maximal error of the instrument might occurre in D/A conversion circuitry which varies according to the characteristics in the resistance bridge.Serial communication makes the volume of operators smaller.