PLC自检信号很多，内部器件也很多，多数使用者未充分发挥其作用。其实，完全可利用它进行PLC自身工作的监控，或对控制对象进行监控。对一个复杂的控制系统，特别是自动控制系统，监控以至进一步能自诊断是非常必要的，它可减少系统的故障，出了故障也好查找，可提高累计平均无故障运行时间，降低故障修复时间，提高系统的可靠性。
ABB ADVANT FIELDBUS CONTROLLER CI626A-1 BOARD 3BSE00427
ABB SNAT-603 CNT MOTOR CONTROLLER CARD ACS AC DRIVE
ABB ACS600 DRIVE CONTROL NDCU-04 CONTROLLER I/O UNIT
RITTAL SK3302110 SK WALL MOUNT AC AIR CONDITIONER 115V
ROSEMOUNT 3000 OXYGEN PROBE CELL REPLACEMENT KIT 9 FT
RELIANCE ELECTRIC 86466-47T 8646647T RECTIFIER STACK
DEZURIK SIGNAL PANEL ASSEMBLY & SWITCH 1254670
IMO ROTARY ROTOR SCREW OIL PUMP C3EBF-200 1-1/8"SHAFT
WESTINGHOUSE 40HP AC MOTOR T FRAME 2700RPM 575V 4P 3PH
ENVIRONMENTAL DIGICON POWER CONTROL PRECIPITATOR
HONEYWELL STD3000 MAU INTERFACE ASSEMBLY 51305348-100
NEW ARMSTRONG CLOSE COUPLED HYDRAULIC PUMP 4280 4030
NELES JAMESBURY 3" SEGMENT BALL VALVE FG03CAGS6XKSGTD
PARKER HYDRAULIC PROPORTIONAL VALVE D31FSE01B4VXP035
VIKING PUMP MODEL 135 QT 135QT
