CI840A ABB

Delay control

It is usually used in the case of switching control.When a switch state changes(such as when switching from on to off),the output action of the controller will be delayed for a period of time before it is given.For example,in the proximity switch commonly used in the production line,when the workpiece is in place,the proximity switch gives a signal,and the next roller is at a distance from the installation position of the proximity switch,so it usually takes a few seconds to start rolling.

chain control

It is also commonly used in switch control occasions.For example,there are three switches,A,B and C.The C switch must be turned on when A and B are turned on at the same time;or when A is turned on,C must be turned on;this relationship is a chain.control.In industrial sites,especially where safety control is involved,chain control is very common.For example,the vent valve in the reactor,when the pressure reaches a certain value,the signal of the pressure switch changes,the vent valve must be opened immediately.

延时控制

通常应用在开关量控制的场合，当一个开关状态变化时(比如由开变关时)，控制器的输出动作要延时一段时间才会给出。比如，在生产线常用的接近开关，当工件就位时，接近开关给出信号，下一个滚筒由于和接近开关安装的位置有一段距离，所以通常要延迟几秒才开始滚动。

连锁控制

也是常用于开关控制的场合，比如有三个开关，A、B和C，C开关必须在A和B同时打开的时候，才能够打开;或者当A打开时，C必须打开;这种关系就是连锁控制。在工业现场中，尤其是在涉及安全控制的场合，连锁控制方式是很常见的。比如反应釜中的放散阀，当压力达到一定值时，压力开关的信号发生变化，则放散阀门必须立刻打开。