7.1引言 7.1.Ⅰ直接数字控制系统(DDC- Direct Digital ControD) input. Digital-to- Actuator process Compute analog converter digital Analog-to- Measurement digital sensor converter 图7-1直接数字控制系统(DDC)7.1 引言 7 .1 .1 直接数字控制系统(DDC—Direct Digital Control) Digital Compute Digital-toanalog converter Actuator process Analog-todigital converter Measurement sensor input digital 图7-1 直接数字控制系统(DDC)