导语：本文介绍了一种应用LM35温度传感器开发的温控系统，重点阐述了系统结构、工作原理以及采样值量化。同时对LM35传感器特性、系统硬件电路设计、软件设计也作了介绍。该系统体积小、成本低、工作可靠，具有很高工程应用价值。

摘要：在民用控制和工业控制领域，温度测量和控制是基础需求。本文详细描述了一种基于LM35AH集成电路温度传感器的温控系统设计，该方案实现了精确的室内环境温度监测，并根据设定点进行加热以维持恒定温度。此外，本文还讨论了如何通过调整电路来适应不同的测量范围，以及如何使用PLM/51语言与ASM混合编程来优化软件性能。

关键词：温控系统，LM35AH, 12位AD转换器, AT89C55单片机, 工程应用价值

引言

在现代技术中，精确的环境监测对于许多设备和操作至关重要。在一些情况下，比如实验室或数据中心，微小的环境变化都可能对设备造成严重影响。为了解决这一问题，我们需要一种能够提供准确且实时信息的小型、高效能且成本低廉的温控解决方案。这篇文章将展示一套基于常规组件（包括AT89C55单片机、12位AD转换器AD574和松下PhotoMOS继电器AQZ202）实现的小型全自动温控装置，该装置利用NS公司生产的一款集成电路类型号为LM35AH，以其线性输出特性而著称。

LM35AH temperature sensor

The LM35 series are highly accurate and stable devices with a linear +10 mV/°C scale factor that is accurate to ±0.5 °C from 0 ° to 50 °C and ±3 °C up to +150 °C. The output voltage is directly proportional to the Celsius temperature (thus allowing easy interfacing). This makes it particularly useful for applications where a high degree of accuracy is required.

System structure and working principle

The control circuit consists of four main parts: the temperature sensor circuit, signal conditioning circuit, A/D conversion circuit, single-chip microcomputer system, and heating control circuit. The working principle involves converting the sensed temperature into an electrical signal by the LM35 sensor and then amplifying this signal using an operational amplifier before it reaches the analog-to-digital converter (ADC) in order to adjust its amplitude within a specific range.

Hardware design details

The hardware design includes both analog circuits such as amplifiers or filters which are used for processing signals from sensors like thermistors or thermocouples; digital circuits such as counters or registers that can be used for counting pulses coming out of these sensors; communication interfaces like UARTs (Universal Asynchronous Receiver Transmitter) needed for data transfer between different components in our system; memory blocks including ROM (Read Only Memory), RAM (Random Access Memory), EPROM etc., which store instructions/data necessary during execution time.

Software design details

Software plays an essential role in controlling our system's operations through programming languages like C/C++, Python etc., where we implement algorithms based on mathematical models developed by experts along with logical reasoning & decision-making rules derived from various input parameters provided by users/sensors themselves via serial communication protocols over RS232 cable connections among other things!