三、万语始于HelloWorld，万物基于点灯之瑞萨RX23E-A 3线RTD PT100测温

一、概述/目的
二、RX23E-A+PT100三线制
2.1 资料来源
2.2 接线图
2.3 工程配置AFE+24ΔΣADC+PGA
2.4 代码
2.5 IIR数字滤波器
三、方案对比

一、概述/目的

介绍工业过程控制中的测温最常用的PT100三线制，使用瑞萨RX23E-A实现3线RTD PT100测温，展示其便捷性，简单对比MCU+MAX31865。

二、RX23E-A+PT100三线制

2.1 资料来源

官方资料-开发板+例程
RX MCU RX23E-A 高精度测量基础知识与应用实战培训 2023-09_v1.0.pdf
RX MCU RX23E-A 高精度测量基础知识与应用实战_实验指南.pdf
RX23E_A_Local_Board_SCH.pdf

2.2 接线图

2.3 工程配置AFE+24ΔΣADC+PGA

rx23ea_local_board_lab
rx23ea_rtd

2.4 代码

float R_RTD_DsadToTemp (float dsad)
{float rrtd = (D_RTD_GAIN * dsad) + D_RTD_OFFSET;        /** Convert DSAD Value to RTD resistance value [ohm]   */uint16_t idx = R_CALC_BinarySearch(s_rtd_table, D_RTD_TABLE_SIZE, rrtd);/** Set a temperature range that includes the value of the argument */float x0 = s_rtd_table[idx];                            /** x0:Temperature range lower limit resistance [ohm]  */float x1 = s_rtd_table[idx + 1];                        /** x1:Temperature range upper limit resistance [ohm]  *//** convert idx to temperature */float y0 = (float) idx + D_RTD_TABLE_TOP_TEMPARATURE;/** convert idx + 1 to temperature */float y1 = (float) (idx + 1) + D_RTD_TABLE_TOP_TEMPARATURE;float f_temp = R_CALC_Lerp(x0, y0, x1, y1, rrtd);       /** Calculated temperature [degree]                     */return f_temp;
}

/** A/D conversion complete for DSAD0? */
if (true == r_dsad0_IsConversionEnd())
{int32_t dsad0_value;        /** Signed 24-bit DSAD0 value                                   */r_dsad0_ClearIrFlag();      /** clear DSAD0 IR flag                                         *//** Get A/D value */{R_Config_DSAD0_Get_ValueResult( &dsad0_reg);/** Flag mask, Sign extension */dsad0_value = (int32_t) ((dsad0_reg & 0x00FFFFFFU) << 8) >> 8;}/** Calculate the temperature [degree] of the reference junction */rtd_temp = R_RTD_DsadToTemp((float) dsad0_value);