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stm32f407的ADC采集值变动较大,啥回事呢?

工程师
2020-10-09 22:12:13     打赏

stm32f407的ADC采集值变动较大,啥回事呢?


以下是电路图和采集到的数据结果:


[2020/7/6 22:08:40 213]  COMB[\\.\COM24]接收208字节:
[2020/7/6 22:08:40 232]  adc now is 2511
adc now is 2515
adc now is 2527
adc now is 2528
adc now is 2545
adc now is 2540
adc now is 2539
adc now is 2568
adc now is 2598
adc now is 2627
humi  is  37 .............

[2020/7/6 22:08:41 211]  COMB[\\.\COM24]接收208字节:
[2020/7/6 22:08:41 223]  adc now is 2527
adc now is 2536
adc now is 2560
adc now is 2566
adc now is 2583
adc now is 2603
adc now is 2646
adc now is 2676
adc now is 2718
adc now is 2743
humi  is  35 .............

[2020/7/6 22:08:42 211]  COMB[\\.\COM24]接收208字节:
[2020/7/6 22:08:42 223]  adc now is 2579
adc now is 2616
adc now is 2655
adc now is 2682
adc now is 2724
adc now is 2758
adc now is 2784
adc now is 2811
adc now is 2852
adc now is 2879
humi  is  32 .............

[2020/7/6 22:08:43 214]  COMB[\\.\COM24]接收208字节:
[2020/7/6 22:08:43 238]  adc now is 2736
adc now is 2775
adc now is 2801
adc now is 2829
adc now is 2865
adc now is 2895
adc now is 2927
adc now is 2941
adc now is 2984
adc now is 3026
humi  is  29 .............

[2020/7/6 22:08:44 212]  COMB[\\.\COM24]接收208字节:
[2020/7/6 22:08:44 223]  adc now is 2891
adc now is 2920
adc now is 2946
adc now is 2977
adc now is 3006
adc now is 3033
adc now is 3070
adc now is 3100
adc now is 3128
adc now is 3147
humi  is  25 .............

[2020/7/6 22:08:45 275]  COMB[\\.\COM24]接收208字节:
[2020/7/6 22:08:45 313]  adc now is 3017
adc now is 3055
adc now is 3088
adc now is 3103
adc now is 3136
adc now is 3163
adc now is 3188
adc now is 3217
adc now is 3242
adc now is 3265
humi  is  22 .............

[2020/7/6 22:08:46 216]  COMB[\\.\COM24]接收208字节:
[2020/7/6 22:08:46 246]  adc now is 3160
adc now is 3184
adc now is 3199
adc now is 3232
adc now is 3243
adc now is 3266
adc now is 3274
adc now is 3298
adc now is 3290
adc now is 3303
humi  is  20 .............

[2020/7/6 22:08:47 216]  COMB[\\.\COM24]接收208字节:
[2020/7/6 22:08:47 244]  adc now is 3265
adc now is 3279
adc now is 3302
adc now is 3295
adc now is 3304
adc now is 3301
adc now is 3317
adc now is 3328
adc now is 3323
adc now is 3331
humi  is  18 .............

[2020/7/6 22:08:48 217]  COMB[\\.\COM24]接收208字节:
[2020/7/6 22:08:48 230]  adc now is 3304
adc now is 3319
adc now is 3319
adc now is 3323
adc now is 3326
adc now is 3324
adc now is 3337
adc now is 3335
adc now is 3327
adc now is 3345
humi  is  18 .............

[2020/7/6 22:08:49 220]  COMB[\\.\COM24]接收208字节:
[2020/7/6 22:08:49 227]  adc now is 3327
adc now is 3346
adc now is 3348
adc now is 3334
adc now is 3350
adc now is 3335
adc now is 3332
adc now is 3323
adc now is 3324
adc now is 3307
humi  is  18 .............

[2020/7/6 22:08:50 219]  COMB[\\.\COM24]接收208字节:
[2020/7/6 22:08:50 246]  adc now is 3331
adc now is 3332
adc now is 3332
adc now is 3311
adc now is 3311
adc now is 3295
adc now is 3303
adc now is 3301
adc now is 3288
adc now is 3295
humi  is  18 .............

[2020/7/6 22:08:51 222]  COMB[\\.\COM24]接收208字节:
[2020/7/6 22:08:51 228]  adc now is 3297
adc now is 3293
adc now is 3290
adc now is 3280
adc now is 3278
adc now is 3271
adc now is 3266
adc now is 3262
adc now is 3250
adc now is 3254
humi  is  19 .............

[2020/7/6 22:08:52 221]  COMB[\\.\COM24]接收208字节:
[2020/7/6 22:08:52 227]  adc now is 3262
adc now is 3266
adc now is 3254
adc now is 3239
adc now is 3231
adc now is 3235
adc now is 3230
adc now is 3234
adc now is 3208
adc now is 3209
humi  is  20 .............

[2020/7/6 22:08:53 225]  COMB[\\.\COM24]接收208字节:
[2020/7/6 22:08:53 237]  adc now is 3226
adc now is 3239
adc now is 3213
adc now is 3203
adc now is 3205
adc now is 3216
adc now is 3202
adc now is 3180
adc now is 3190
adc now is 3172
humi  is  21 .............

[2020/7/6 22:08:54 223]  COMB[\\.\COM24]接收208字节:
[2020/7/6 22:08:54 229]  adc now is 3183
adc now is 3191
adc now is 3176
adc now is 3163
adc now is 3163
adc now is 3168
adc now is 3151
adc now is 3158
adc now is 3144
adc now is 3152
humi  is  22 .............

[2020/7/6 22:08:55 222]  COMB[\\.\COM24]接收208字节:
[2020/7/6 22:08:55 228]  adc now is 3147
adc now is 3139
adc now is 3138
adc now is 3134
adc now is 3134
adc now is 3109
adc now is 3124
adc now is 3105
adc now is 3102
adc now is 3099
humi  is  23 .............

[2020/7/6 22:08:56 225]  COMB[\\.\COM24]接收208字节:
[2020/7/6 22:08:56 233]  adc now is 3115
adc now is 3105
adc now is 3110
adc now is 3098
adc now is 3097
adc now is 3095
adc now is 3081
adc now is 3096
adc now is 3071
adc now is 3038
humi  is  24 .............

[2020/7/6 22:08:57 227]  COMB[\\.\COM24]接收208字节:
[2020/7/6 22:08:57 230]  adc now is 3075
adc now is 3071
adc now is 3047
adc now is 3003
adc now is 2968
adc now is 2942
adc now is 2911
adc now is 2872
adc now is 2825
adc now is 2783
humi  is  27 .............

[2020/7/6 22:08:58 226]  COMB[\\.\COM24]接收208字节:
[2020/7/6 22:08:58 229]  adc now is 2851
adc now is 2813
adc now is 2780
adc now is 2749
adc now is 2720
adc now is 2695
adc now is 2651
adc now is 2641
adc now is 2600
adc now is 2566
humi  is  33 .............

[2020/7/6 22:08:59 227]  COMB[\\.\COM24]接收208字节:
[2020/7/6 22:08:59 230]  adc now is 2591
adc now is 2567
adc now is 2528
adc now is 2512
adc now is 2478
adc now is 2443
adc now is 2426
adc now is 2398
adc now is 2380
adc now is 2352
humi  is  39 .............

[2020/7/6 22:09:00 229]  COMB[\\.\COM24]接收208字节:
[2020/7/6 22:09:00 237]  adc now is 2345
adc now is 2329
adc now is 2318
adc now is 2301
adc now is 2287
adc now is 2282
adc now is 2290
adc now is 2275
adc now is 2272
adc now is 2263
humi  is  43 .............

[2020/7/6 22:09:01 230]  COMB[\\.\COM24]接收208字节:
[2020/7/6 22:09:01 238]  adc now is 2238
adc now is 2248
adc now is 2240
adc now is 2241
adc now is 2243
adc now is 2226
adc now is 2238
adc now is 2250
adc now is 2230
adc now is 2231
humi  is  45 .............

[2020/7/6 22:09:02 231]  COMB[\\.\COM24]接收208字节:
[2020/7/6 22:09:02 239]  adc now is 2224
adc now is 2226
adc now is 2240
adc now is 2236
adc now is 2248
adc now is 2243
adc now is 2251
adc now is 2270
adc now is 2259
adc now is 2278
humi  is  44 .............




关键词: stm32f407     ADC     A/D     数据采集     数模    

工程师
2020-10-09 22:41:22     打赏
2楼

1、基准电压是否稳定,可以用示波器看,是否叠加了干扰信号。

2、检测端,示波器看是否叠加干扰信号。

3、1,2均没有的话,再检查程序。


工程师
2020-10-09 22:45:52     打赏
3楼

一般采样多次,然后进行相关算法(如去掉最低和最高,最后进行求和平均)处理,这样数据较准确


工程师
2020-10-09 22:51:51     打赏
4楼

谢谢前面2位坛友的指点!


我测了,目前电源纹波峰峰值35mv左右 ,是不是这个纹波对于adc来说有点大 电源用的24v+xl1509->5v+MP2161->3.3v  电源布线感觉问题不大 但是1509纹波是有一点点的  不如mp1584这种 ,请问这样的纹波会不会造成stm32f407的adc不稳定


湿度采集入下图所示 使用f103的板子 感觉是挺稳定的 f407的板子就不稳定,两个板子是两个人布局,程序也是两个人写的 但是读取的原始adc值就是f103较为未定,f407波动较大,我感觉布线的问题不太大,地平面还算完整。



工程师
2020-10-09 22:57:19     打赏
5楼

看电路,基准的稳定度肯定有影响的:3.3V然后经过一个4148二极管给VREF供电,而且所有数字VDD和VREF连接在一起;
另外,VSSA我记得是模拟的地,你确定连接到3.3V还能正常工作?


菜鸟
2020-10-12 10:27:41     打赏
6楼

也有可能是AD输入阻抗过大引起的


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