“工业控制微型计算机应用技术”讲座——第五讲 过程输出通道

一、概述过程输出通道的功能是将计算机的输出代码变换成相应的信号直接控制执行机构。由于控制对象所需信号种类不一样,因而过程输出通道包括有模拟量输出通道、开关量输出通道、数字量输出通道以及脉冲量输出通道等几种类型。计算机用于过程控制系统,过程输出通道是不可缺少的重要部分。象过程输入通道一样,依现场所需,过程输出通道也分成隔离型和非隔离型两类。     

烤烟炉多点测温与数据采集系统设计

介绍了一种利用铂电阻作为温度传感器，测温范围在0～200℃，输出电压范围在0～2V的具有较高精度和分辨率的线性多点测温系统的设计方案，并通过多路/分时模拟量输入通道将测温电路输出的多路信号依次循环输入计算机，实现了对炉温的实时检测。     

用线性和对数特性实现中频放大电路的设计

阐述中频放大器电路的组成原理、设计方法和测试方法。整个系统的组成包括线性通道、对数通道和稳压电源三部分。线性通道中,使用高性能低噪音宽带差分放大器AD8350进行线性放大,电路输入匹配于50Ω,具有"单端-差分"转换网络,增益为18 dB,输出功率范围宽达-90~+8 dBm(1dB压缩点)。功率分配网络用于线性输出和对数放大器的输入。对数通道中,采用高动态范围宽带对数放大器AD8309作为主要部件,对数放大器输出的电压信号与输入功率的dBm值呈线性关系。该信号用以检查线性通道是否正常,并可估计整机性能。在输入功率为-68~-8 dBm时,对数放大器输出电压范围为0.19~2.06 V。     

多种信号源隔离输入的信号调理模块设计

信号调理模块介于传感器和A／D模块之间，是外部信号进入计算机的通道。本文针对复杂现场环境下因为外部传感器的地电位不同而给计算机带来的干扰，设计一种回路间隔离的、具有多种输入模式的信号调理电路；详细分析该电路在各种输入模式下的工作原理，并给出工程上实用的电路。     

交流电动机软起动全数字可控硅触发板

电动机软起动控制柜,目前多采用分立元件或KC系列集成块组成触发板,包括测量、保护部分,电路复杂,可靠性及控制精度都较差;尤其是可调整的点很多,难以达到高性能技术指标。新开发的DWK触发板,采用三只单片计算机协调工作,大量软件代替了硬件。同步变压器焊接在印刷板上,输入、输出光电隔离,无脉冲变压器。自过零点检测至触发脉冲输出的整个通道电路没有储能元件(电感、电     

一个非自治电路混沌特性的计算机分析与研究

该文首先分析了Logistic映射的一些典型的混沌特性，然后运用与其相类比的分析研究方法，诸如时间序列分析方法、相图分析方法和分岔图分析方法，对一个非自治电路进行了计算机分析与研究。通过对描述该非自治电路的非线性微分方程进行求解和计算机分析，可以看到，当输入电压的幅值改变时，该电路系统的动力学特性对输入电压幅值有很强的敏感性。在对该非自治电路的分岔图进行了详细的计算机分析后，指出了该非自治电路从倍周期通向混沌的分岔点。以此，说明了该非自治电路是典型的具有混沌特性的非线性电路。     

基于最小二乘估计的数据采集通道标定方法

由于数据采集通道受外界环境因素的影响,A/D转换器输出数值与输入模拟信号之间对应的理想数学关系式不再成立;为了得出输入信号与A/D输出数值之间的对应关系,在分析电路所采用器件电气特性的基础上,建立了数据采集通道的标定模型,并给出了基于最小二乘原则的模型参数估计方法;通过对直流电压信号的直流准确度和对正弦交流信号有效值的测试,证明了该模型的正确性和可行性.     

金升阳科技—VRB_D-5W系列模块电源

金升阳科技（MORNSUN）近日推出宽电压输入隔离稳压单输出型DC-DC模块电源VRB_D-5W系列。该系列产品输入电压允许变化范围宽，输出电压稳定度较高，内有多种保护电路，可持续短路，自恢复，特别适用于输入电压变化较大或输出电压要求隔离稳压的场合。如工业控制和远距离直流供电系统。     

脉冲变压器隔离电路技术及其应用

一、概述智能仪表的可靠性是由多种因素决定的,其中智能仪表的抗干扰性能是衡量可靠性的重要指标。在智能仪表中,各种干扰来自三个方面:通过电磁波辐射进入系统的空间干扰,通过输入通道和输出通道进入系统的过程通道干扰,以及供电干扰。在这些干扰中应重点防止的是过程通道干扰。智能仪表接收来自现场、仪表室操作面板上的各种信号,为了避免传输干扰的影响,大多采用隔离绝缘的办法提高抗干扰的能力。对于智能仪表来说,经常采用的隔离方式有光电耦合隔离电路和脉冲变压器隔离电路。这两种隔离电路输入/输出电路的接地可自由选择具有很高的隔离性能,能抑制各种强干扰。与光电隔离电路相比,脉冲变压器隔离电路具有一些独特的优点,如功耗     

基于赋初值BP算法的模拟电路故障的诊断

提出了采用赋初值BP神经网络的方法,进行模拟电路故障的诊断;该方法分两步实现:首先对网络输入层到末级隐层之间权值的设计,能简化网络结构,缩短训练时间;其次对BP网络输出层权值和阈值的设计,以加快收敛速度、抑制局部极小、减少了学习过程的振荡现象;文中通过心电信号放大器电路实例,对其诊断方法的原理与实现进行了较深入的研究,并通过计算机仿真,模拟诊断该电路,结果证明:该方法具有鲁棒性、准确性与快速性。     

Concurrent online testing of identical circuits using nonidentical input vectors

Current designs may contain several identical copies of the same circuit (or functional unit). Such circuits can be tested by comparing the output vectors they produce under identical input vectors. This alleviates the need to observe the output response, and facilitates online testing. We show that testing of identical circuits by output comparison can be done effectively even when the input vectors applied to the circuits are not identical. This allows concurrent online testing even when the circuits are not driven from the same source during functional operation. We investigate several issues related to this observation. We investigate the use of both structural and functional analysis to identify situations where nonidentical input vectors can be used for fault detection based on output comparison. We also consider the use of observation points to improve the fault coverage. We present experimental results to support the discussion and the use of nonidentical input vectors for concurrent online testing of identical circuits.     

基于MSP430的全箭模态试验信号通路控制器的研制

在全箭模态等试验控制系统中,为解决模态试验系统激振器通道数目与激励测量模块通道数量不一致,而导致在实验过程中,连接、更换通道连接线时,不仅耗时而且经常出错等问题,设计并实现了一种多路信号通道控制器,该信号通道控制器可以实现多达32路通道与32路通道的信号的任意连接和智能在线切换。配置连接的通道信号线间导通,未配置连接的通道之间成高阻抗状态。试验人员仅需将测量通道连接在输出端,将模态试验系统测量模块通道连接在输入端,就可以通过控制器液晶屏进行通道配置,实现输入、输出通道的任意连接和在线通道切换。     

高精度远程隔离型多路AI/AO电路设计

设计了一种基于TMS320LF2407的模拟量输入电路(AI)和模拟量输出电路(AO),成功解决了大型远程工业控制系统中存在的三个问题.实际的工程应用表明,该电路具有良好的应用前景.     

基于小波包分形的电力电子故障诊断方法

针对现有电力电子故障诊断的问题,提出了一种基于小波包分形的电力电子故障的诊断方法.首先使用3层小波包对电路输出电压波形进行分解、消噪和重构等预处理,以获得不同频带的重构信号,然后再计算各个重构信号的分形维度,提取出相应的故障特征;最后以此作为输入数据来训练支持向量机,实现电力电子故障的诊断.以三相整流电路为例进行实验,实验结果表明该方法能有效地提取电力电子故障诊断的故障特征,提高故障诊断的准确率,可有效地应用于电力电子系统的故障诊断.     

通用型变频器CAD软件的开发

本文介绍了基于Windows的通用型变频器CAD软件、软件实现了变频器主电路参数的设计、电路图形的输。入、编辑、电路性能的仿真、输出、数据库管理、辅助工具、帮助、系统演示等功能，软件具有开发平台先进、功能丰富、界面友好、算法先进等一系列特点。     

Improving the efficiency of direct-memory-access output operations

The improvements in throughput expected from direct-memory-access channels are not realized with simple input/output routines. For output operations, the improvements can be realized through the provision of a separate data buffer area in memory that may be accessed by the peripheral while the primary buffer area is being manipulated by the program. The method may be extended to peripherals that require error checking after output.     

Automata for direct radix conversion

Modular logic circuits are described that directly transform on a digit by digit basis a number from one radix to another. Each device—an automaton—is of combined Moore-Mealy design of which the Moore output is a coefficient in the transformed radix, and the Mealy output is an untransformed residue passed on to the next identically designed circuit. Each logic circuit is completely independent of word length, and transformation relative to the input string is exact at each instant of time with all transformed digits simultaneously available. For fractional number conversion, any specified accuracy can be obtained merely by the addition of more modular logic circuits to the chain.     

Optically injected logic circuits for remote-powered systems on a chip

This paper reviews the concept of optically injected logic circuits and investigates their implementation in nanometer CMOS technologies. Optically injected circuits are powered via an optical beam, i.e. they do not require a local power supply and distribution network. A complete set of digital cells has been designed and simulated, and key building blocks of the logic family have been fabricated and tested in a standard 180 nm CMOS technology. The paper also discusses the design and implementation of optically injected circuits for clock distribution, input/output, analog-to-digital and digital-to-analog conversion. All these circuits are immediately applicable in wireless biomedical implants or contactless smart cards. They can also be used in other systems-on-chip (SoC), in which very low power operation can be replaced by remote-powered operation.     

Logic operations based on single neuron rational model

This paper focuses on phase analysis to explore the single neuron local arithmetic and logic operations on their input conductances. Based on the analysis of the rational function model of local spatial summation with the equivalent circuits for steady-state membrane potentials, the prototypes spatial summation with the equivalent circuits for steady-state membrane potentials, the prototypes of logic operations are constructed. A mapping from a partition of input conductance space into functionally distinct phases is described and the multiple mode models for logic operations are established. The transitions from output voltage to input conductance in logic operations are also discussed for the connections between neurons in different layers. Our theoretical studies and software simulations indicate that the single neuron local rational logic is programmable and the selection of these functional phases can be effectively instructed by presynaptic activities. This programmability makes the single neuron more flexible in processing the input information.     

基于C8051F005单片机的飞机供电系统模拟器

介绍了某型号飞机电源系统模拟器的结构和设计原理,详细介绍了C8051F005单片机及其外围的模拟量输入输出电路、数字量输入输出电路和供电电路,并对系统的软件设计进行了阐述,实验证明此模拟器实时性好,稳定性高,能满足系统要求。