PLC按结构形式可分为整体式和模块式。整体式PLC将电源、CPU、I/O部件都集中装在一个机箱内。模块式PLC结构是将PLC各部分分成若干个单独的模块，如CPU模快、I/O模快等。考虑到自来水厂改建(特别是节能、更换旧设备方面)、扩建和PLC故障率95%都是发生在I/O部件损坏;同时模块式PLC的配置灵活，装配和维修方便，水厂设备、工艺的改变只要将相应的I/O模快更换或扩展再经编程就可方便实现自动化。因此，从长远来看，提倡选择模块式PLCLITE LS70Power supply Rectifier filter board +upc1237 Rectifier Filter Board Kit 50v10000uf 15A LM1875 TDA7294 LM3886 AM-60BD 4*63V/470UFAssembeld 6X 10000uf 80V 8 Capacitors Schottky Rectifier Filter Board 120A35A Audio Power Supply Amp Board 10000uf *4 50VHPOO Single Power Supply Rectifier Filter Finished Board NOVER 2*10000UF/50V 50V 10000uf 15A LM1875 TDA7294 LM3886 Kit LM3886TF Class A Power Amp Board A8 1pc. - Panasonic Power Amplifier Rectifier Filter Board 8800uFDual Power Rectifier Filter Board AC 9 17V DC ± 12 24VBurkhardt Weber Rotierende Kupplung 390610.00.11Bosch Servo I Board 1070068008-102Bosch Input Modul 1070047961-105401Bosch Output Card 048485-205401-201303 (048485205401201303)Bosch Rexroth CNC Monitor TFT-LCD-TFT-Kit 1070922320-101