接地是进步电子设备电磁兼容性(EMC)的有效手段之一。正确的接地,既能抑制电磁干扰的影响,又能抑制设备向外发出干扰;而错误的接地,反而会引进严重的干扰信号,使PLC系统将无法正常工作。 来自PLC系统内部的干扰 主要由系统内部元器件及电路间的相互电磁辐射产生,如逻辑电路相互辐射及其对模拟电路的影响,模拟地与逻辑地的相互影响及元器件间的相互不匹配使用等。 变频器干扰 一是变频器启动及运行过程中产生谐波对电网产生传导干扰,引起电网电压畸变,影响电网的供电质量;二是变频器的输出会产生较强的电磁辐射干扰,影响周边设备的正常工作。MFR. PART NUMBER DESCRIPTION 1756-A10 10 SLOT CONTROLLOGIX CHASSIS 1756-A13 13 SLOT CONTROLLOGIC CHASSIS 1756-A17 CHASSIS 17 SLOT CONTROLLOGIX 1756-A4 4 SLOT CONTROLLOGIX CHASIS 1756-A7 7 SLOT CONTROLLOGIX CHASSIS 1756-BA1 LOGIX5000 BATTERY ASSEMBLY 1756-CFM 2 CHANNEL /2 OUT CONFIGURABLE FLOWMETER 1756-CNB CONTROLNET BRIDGE MODULE 1756-CNBR CONTROLNET REDUNDANT BRIDGE MODULE 1756-CP3 LOGIX5000 RS232 PROGRAMMER CABLE 1756-DHRIO 2 CHANNEL DH+ AND/OR RIO SCANNER 1756-DNB DEVICE NET BRIDGE/SCANNER MODULE 1756-DPALEN CONTROLLOGIC SYSTEM DOCUMENTATION SET PRINTED 1756-ENET ETHERNET/IP BRIDGE MODULE 1756-GTWY CONTROLLOGIC GATEWAY CONFIGURATION SOFTWARE 1756-GTWYR SUPT REINSTATEMENT CONTRACT FOR 1756GTWY 1756-GTWYS SUPT RENEWAL CONTRACT FOR 1756GTWY 1756-HSC 2 CHANNEL /4 OUTPUT HIGH SPEED COUNTER 1756-IA16 79-132 VAC INPUT 16PTS 1756-IA16I 79-132 VAC ISOLATED INPUT 16PTS 1756-IA8D VAC DIAGNOSTIC INPUT 8PTS 1756-IB16 VDC INPUT 16PTS 1756-IB16D VDC DIAGNOSTIC INPUT 1756-IB16I VDC ISLOTED INPUT 16PTS 1756-IB32 VDC INPUT 32PTS 1756-IC16 VDC INPUT 16PTS 1756-IF16 ANALOG INPUT-CURRENT/VOLTAGE 16PTS 1756-IF6I ISOLATED ANALOG INPUT-CURRENT/VOLTAGE 6PTS 1756-IF8 ANALOG INPUT-CURRENT/VOLTAGE 8PTS 1756-IH16I VDC ISOLOTED INPUT 16PTS