AIM0006  数字量输入模块  滤除由输入端引入的干扰噪声

AIM0006 数字量输入模块是一种用于连接外部的机械触点和电子数字式传感器的设备，例如二线式光电开关和接近开关等。该模块的主要作用是将从现场传来的外部数字信号的点评转换为PLC内部信号电平。

AIM0006数字量输入模块在输入电路中一般设有RC滤波电路，以防止由于输入触点抖动或外部干扰脉冲引起的错误输入信号，其输入电流一般为数毫安。

数字量输入模块的滤波电路主要作用是滤除由输入端引入的干扰噪声，以及消除因外接输入触点动作时产生的抖动导致的不良影响。滤波电路能够只允许一定频率范围内的信号成分正常通过，而阻止另一部分频率成分通过。

在实际应用中，如果输入信号存在干扰或噪音，可以通过调整输入滤波时间来滤除这些干扰，从而避免误动作。滤波电路的时间常数决定了输入滤波时间的长短，对于某些输入模块，输入延迟时间可以调整。

此外，需要注意的是，AIM0006数字量滤波是对电压信号的延时滤波，相当于一个低通滤波器，只能滤除高频的干扰脉冲，不能用于滤除低频干扰信号。因此，在设计滤波电路时，需要根据实际的应用场景和信号特性来选择合适的滤波方案。

The AIM0006 Digital input module is a device used to connect external mechanical contacts to electronic digital sensors such as wire photoelectric switches and proximity switches. The main function of the module is to convert the comments of the external digital signal from the field into the PLC internal signal level.

The AIM0006 digital input module generally has a RC filter circuit in the input circuit to prevent the wrong input signal caused by the input contact jitter or external interference pulse, and its input current is generally a few milliamps.

The main function of the filter circuit of the digital input module is to filter the interference noise introduced by the input end and eliminate the adverse effects caused by the jitter caused by the action of the external input contact. The filter circuit can only allow the signal components within a certain frequency range to pass normally, and prevent the passage of other frequency components.

In practical applications, if there is interference or noise in the input signal, the interference can be filtered out by adjusting the input filtering time, so as to avoid misoperation. The time constant of the filter circuit determines the length of the input filtering time, and the input delay time can be adjusted for some input modules.

In addition, it should be noted that AIM0006 digital filter is a delay filter of voltage signals, equivalent to a low-pass filter, can only filter high-frequency interference pulses, can not be used to filter low-frequency interference signals. Therefore, when designing the filter circuit, it is necessary to choose the appropriate filtering scheme according to the actual application scenario and signal characteristics.