描述
梯形图编程语言是从继电器控制系统原理图的基础上演变而来的。PLC的梯形图与继电器控制系统梯形图的基本思想是一致的，但是在使用符号和表达式等方面有一定区别。
梯形图具有形象、直观、简单明了，易于理解的特点，特别适合开关量逻辑控制，是PLC最基本、最普遍的编程语言。
Yokogawa YFCT Flow Computing Totalizer YEW YFCT-ST3A*A
Cutler-Hammer CH/Westinghouse Digitrip RMS/R 810 DB-50
Benshaw RSi025S44W RSi 25 HP Sensorless Vector VS Drive
Allen Bradley AB 1336E-B015-AA-EN Impact 15 HP VS Drive
Mitsubishi FR-A221E-15K AC Inverter Drive A200 20 HP
Westinghouse 5980C01G03 4000 Amp DSL Truck Fuse E4000
Cutler Hammer 6DSL-E4000 4000 Amp DSL Truck Fuse 600VAC
Yokogawa PU40 Power Supply PU40-1N PU401N H70926005 PLC
GE Fanuc IC600BF948 Comm Control Rev N & P
Federal Pacific Breaker XM632500 500 Amp 500Amp 500A A
Cutler Hammer Eaton Breaker LS360600E LS36T600E LSE 600
Micro Motion F050SR113SUR Mass Flow Sensor MicroMotion
Pacific Scientific SC902-001-01 Servo Controller NIB
Square D Mod 6 Motor Control Center Model 6 800 A MCC
