Thirdly , the range switch circuit and filter circuit are designed in the analog input channel . to realize the safe high speed acquisition , the interface circuits are separated from the function circuits , and the isolation power with high performance and digital isolator is used to restrain the common mode disturb and noise of the input 3 .模拟输入通道设计有量程切换电路和滤波电路,并且采用了屏蔽、浮置技术和磁耦隔离技术,使用了高性能的隔离电源和磁电耦合器,有效地抑制了输入信号的共模干扰和噪声,实现了安全、高速的数据采集。
The precious method to simulate earthquake accelerations is not perfect because the points on the interface still move according to the simulated acceleration when the points " motion ends , which is obviously a paradox . if the points " velocity is not zeroized , soil ' s damage value based on shear stress ' s peaks or extrema is overestimated in multi - point input analysis . the new method ' s rationality is analyzed 以往人工合成的地震波在地震结束时即地震加速度恒为零时速度不为零，这与合成地震动是“模拟输入点从静止到运动再到静止的运动过程”这一要求不一致，同时导致时域内多点输入分析时差动力过大以至算出的损伤值过大，于是本文提出了简易的地震动速度归零化方法并分析了其合理性。
Firstly , a data acquisition circuit was designed , which is consisted of ad420 , dac702 and ad7701 . then , comparing with different usb control ics , an2131 was selected to achieve the control of data acquisition and usb communication . detailed rules to develop a usb device general purpose drivers were introduced , and the virtual instrument application software was developed basing on labview 首先是数据采集卡的制作,包括由ad420 、 dac702数模转换芯片构成的模拟输出通道,由ad7701 、 ad8200构成的模拟输入通道;然后比较几种不同的usb接口芯片,选择带usb接口的an2131微处理器实现数据采集的控制和usb传输功能;之后是usb设备驱动程序的开发和基于labview的虚拟仪器应用程序的设计。
Plc is widely used in automatic control for its strong function , high reliability , wide applicability , modular structure and etc . many customer services , such as showing process - flow charts , displaying dynamic - data - base interfaces , editing tables , generating charts , managing production and etc , can be provided by connecting personal computers ( pcs ) to a plc network . in a plc - pc system , plcs , which serves as the low - level units , are used to collect and control the data , ( for example , the on / off quantities and analog input / output quantities ) 把个人计算机连入plc网络可以向用户提供诸如工艺流程图显示、动态数据画面显示、报表编制、趋势图生成、窗口技术以及生产管理等多种功能，作为底层单元的plc完成对现场开关量、模拟输入输出量的控制处理，而利用微型计算机良好的人机对话界面和数据处理功能，实现对一台或多台plc进行监控，充分发挥plc可靠、灵活的控制性能和计算机在管理、监控等方面的优势，提高控制系统的整体自动化程度。
The bottleneck of hybrid filter banks adc system is that it cannot sample directly higher radio frequency signal because of lower analog input bandwidth of its adc . in order to remove it , a kind of downsampler model based on nyquist and bandpass sampling theorem is presented , analyzed and proved in time and frequency domain , in addition a downsampler is designed according to the model . on the basis of hybrid filter banks adc system , a class of high speed hybrid filter banks adc system is proposed 针对混合滤波器组adc系统因其adc模拟输入带宽低而不能对频率较高的射频模拟信号进行模/数转换的瓶颈，作者提出了一种基于nyquist采样定理和带通采样定理的抽取器数学模型，对该数学模型进行了时域、频域的分析证明后，设计了一种基于该数学模型的sha抽取器，进而在混合滤波器组adc系统的基础上，提出了高速混合滤波器组adc系统。
The system introduces 991 ultra - low frequency pick up , and takes the vibration signal as the simulation input of practical measurement , which makes the s ystem can measure the ultra - low frequency vibration of long , large , tall and flexible structures and the low frequency vibration of engineering and site 系统引入991型超低频拾振器，将其拾取的振动信号作为本系统实际应用测试中模拟输入，使系统可对长大高柔结构的超低频振动和一般工程及场地的低频振动进行测量。
This series of products can be applied to heating furnace , industrial kiln semiconductor stove , precise temperature control of reaction caldron , boiler heat treatment , temperature control and process control system field such as petrochemical industry light industrial machinery and so on . intelligent manipulator is matching product of pid regulator or dcs and other system , which mainly use to manual regulation under the system running or special condition and to carry out operate as a backup instrument when main machine has happened failure or maintenance . according to field regiurement 具有5个模拟输入in1 - in5 2个模拟输出out1 out2 ，一个开关量输入di ， 2个开关量输出和丰富的控制算法，适用于锅炉汽包水位三冲量控制或两冲量控制并可带汽包水位压力补偿功能适用于一般工业过程中温度压力液位流量等各种过程参数的串级控制，前馈控制双路控制等，并可带后备操作器。
