请帮我翻译一下这段话好吗，关于PLC的，不要机器翻译呀

来源：百度知道 编辑：UC知道 时间：2024/06/28 14:54:55
2.Relay circuits :the Roots of PC Logic
PCs historically originate in relay-based control systems.And although the integrated circuits and internal logic of the PC have taken the place of the discrete relays,timers,counters,and other such devices,actual PC operation proceeds as if those discrete devices were still in place.PC control,however,also provides computer capabilities and consistency to achieve a great deal more flexibility and reliability than is possible with relays.
The symbols and other control concepts used to describe PC operation also come from relaybased control and form the basis of the ladder-diagram programming method.Most of the terms used to describe these symbols and concepts,however,originated as computer terminology.

大意如下：：~~~~~~

Relay circuits :the Roots of PC Logic
继电器电路：PC逻辑之根源

PCs historically originate in relay-based control systems.
PC源于基于继电器的控制系统。

And although the integrated circuits and internal logic of the PC have taken the place of the discrete relays,timers,counters,and other such devices,actual PC operation proceeds as if those discrete devices were still in place.
虽然PC集成电路和内部逻辑早已取代离散中继器、计时器、计数器和其它此类元件，但在实际工作中，这些设备好像依然存在于PC中各对应位置上。

PC control,however,also provides computer capabilities and consistency to achieve a great deal more flexibility and reliability than is possible with relays.
PC控制具有计算机的某些功能和一致性，因而相对中继器而言，其灵活性和可靠性大为增加。

The symbols and other control concepts used to describe PC operation also come from relaybased control and form the basis of the ladder-diagram programming method.
用于描述PC工作的这些符号和其它控制思想也源于基于中继器的控制，也是形成梯行图编程法的重要基石。

Most of the terms used to describe these symbols and c