EMERSON A6370D 电源模块 自动化设备卡件模块供应

EMERSON A6370D 电源模块 自动化设备卡件模块供应

梯形图程序中的常开、常闭触点不是实际的物理触点。它们只是反映与现场物理开关的状态相对应的输入、输出映像寄存器或数据寄存器中的相应位的状态，在PLC中认为常开触点是对位寄存器状态进行“读取”操作，而常闭触点则是对位寄存器进行“取反”操作。

梯形图程序中的线圈不是实际物理线圈，无法用它来直接驱动现场元件的执行机构。输出线圈中的状态会直接传输到输出映像寄存器的相应位中去，然后用该输出映像寄存器位中的状态“1”（高电平）或“0”（低电平）去控制输出电路中相应电路，并经功率放大之后去控制PLC的输出器件（继电器、晶体管或可控硅），进而使其触点通断来控制外部现场元件的执行机构。

在编制梯形图程序时，PLC内部继电器的触点原则上可以无限次调用，因为存储单元中的位状态可重复读取；而继电接触器控制电路中的继电器触点数是由继电器的结构形式决定，因而也会随着结构形式的确定而固定下来，其数量是有限的。要特别强调的是，在PLC中一般情况下在同一梯形图程序中线圈通常只能调用一次，因此应尽量避免重复使用同一地址编号的线圈 

The normally open and normally closed contacts in the ladder diagram program are not actual physical contacts. They only reflect the state of the corresponding bit in the input, output image register or data register corresponding to the state of the physical switch on the spot. In the PLC, it is considered that the normally open contact is the "read" operation on the state of the bit register, and the normally closed contact is the "reverse" operation on the bit register.

The coil in the ladder diagram program is not an actual physical coil and cannot be used to directly drive the actuator of the field element. The state in the output coil is directly transmitted to the corresponding bit of the output image register, and then the state "1" (high level) or "0" (low level) in the output image register bit is used to control the corresponding circuit in the output circuit, and the output device (relay, transistor or thyristor) of the PLC is controlled after power amplification. And then make its contacts on and off to control the external field components of the actuator.

In the preparation of ladder diagram program, the contacts of the relay inside the PLC can be called unlimited times in principle, because the bit state in the storage unit can be read repeatedly; The relay contacts in the control circuit of the relay contactor are determined by the structural form of the relay, and therefore will be fixed with the determination of the structural form, and the number is limited. In particular, it should be emphasized that under normal circumstances, the coil in the same ladder diagram program can usually only be called once, so the repeated use of the same address number of the coil should be avoided