NTC temperature sensor going to A:D input. Topology is: (Vref or 3.3V) -> Series_resistor -> A:D_input -> NTC -> GND. Easy modification of NTC parameters w/o recompile of library
ntc.cpp@6:8e6bd0f9877b, 2017-04-12 (annotated)
- Committer:
- loopsva
- Date:
- Wed Apr 12 16:56:27 2017 +0000
- Revision:
- 6:8e6bd0f9877b
- Parent:
- 5:9655397ba539
- Child:
- 8:781d00449dd7
changed the way get_ntc_beta is done. Now a single commanf
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
loopsva | 0:c0bdc272d5da | 1 | /* |
loopsva | 0:c0bdc272d5da | 2 | * mbed library program |
loopsva | 0:c0bdc272d5da | 3 | */ |
loopsva | 0:c0bdc272d5da | 4 | |
loopsva | 0:c0bdc272d5da | 5 | #include "mbed.h" |
loopsva | 0:c0bdc272d5da | 6 | #include "ntc.h" |
loopsva | 0:c0bdc272d5da | 7 | |
loopsva | 0:c0bdc272d5da | 8 | NTC::NTC(PinName p_ana, const NTC_TypeDef *ntc_parameter) : |
loopsva | 0:c0bdc272d5da | 9 | _ana(p_ana) |
loopsva | 0:c0bdc272d5da | 10 | { |
loopsva | 0:c0bdc272d5da | 11 | ntc_set_data = *ntc_parameter; |
loopsva | 0:c0bdc272d5da | 12 | rawdata = NULL; |
loopsva | 0:c0bdc272d5da | 13 | } |
loopsva | 0:c0bdc272d5da | 14 | |
loopsva | 0:c0bdc272d5da | 15 | NTC::NTC(PinName p_ana) : |
loopsva | 0:c0bdc272d5da | 16 | _ana(p_ana) |
loopsva | 0:c0bdc272d5da | 17 | { |
loopsva | 0:c0bdc272d5da | 18 | ntc_set_data = ntc_std_paramtr; |
loopsva | 0:c0bdc272d5da | 19 | rawdata = NULL; |
loopsva | 0:c0bdc272d5da | 20 | } |
loopsva | 0:c0bdc272d5da | 21 | |
loopsva | 0:c0bdc272d5da | 22 | uint16_t NTC::read_ad_reg() { |
loopsva | 0:c0bdc272d5da | 23 | rawdata = _ana.read_u16(); |
loopsva | 0:c0bdc272d5da | 24 | return rawdata; |
loopsva | 0:c0bdc272d5da | 25 | //return 19918; //85.00c * ntc=10k, b=3434, rser=3320 |
loopsva | 0:c0bdc272d5da | 26 | } |
loopsva | 0:c0bdc272d5da | 27 | |
loopsva | 0:c0bdc272d5da | 28 | int NTC::get_ntc_res() { |
loopsva | 0:c0bdc272d5da | 29 | return ntc_set_data.ntc_res; |
loopsva | 0:c0bdc272d5da | 30 | } |
loopsva | 0:c0bdc272d5da | 31 | |
loopsva | 6:8e6bd0f9877b | 32 | int NTC::get_ntc_beta(int curve) { |
loopsva | 0:c0bdc272d5da | 33 | int beta = 0; |
loopsva | 0:c0bdc272d5da | 34 | switch (curve) { |
loopsva | 5:9655397ba539 | 35 | case B0_50: |
loopsva | 5:9655397ba539 | 36 | beta = ntc_set_data.ntc_beta_0050; |
loopsva | 5:9655397ba539 | 37 | break; |
loopsva | 0:c0bdc272d5da | 38 | case B25_50: |
loopsva | 0:c0bdc272d5da | 39 | beta = ntc_set_data.ntc_beta_2550; |
loopsva | 0:c0bdc272d5da | 40 | break; |
loopsva | 0:c0bdc272d5da | 41 | case B25_80: |
loopsva | 0:c0bdc272d5da | 42 | beta = ntc_set_data.ntc_beta_2580; |
loopsva | 0:c0bdc272d5da | 43 | break; |
loopsva | 0:c0bdc272d5da | 44 | case B25_85: |
loopsva | 0:c0bdc272d5da | 45 | beta = ntc_set_data.ntc_beta_2585; |
loopsva | 0:c0bdc272d5da | 46 | break; |
loopsva | 0:c0bdc272d5da | 47 | case B25_100: |
loopsva | 0:c0bdc272d5da | 48 | beta = ntc_set_data.ntc_beta_25100; |
loopsva | 0:c0bdc272d5da | 49 | break; |
loopsva | 5:9655397ba539 | 50 | case B_OTHER: |
loopsva | 5:9655397ba539 | 51 | beta = ntc_set_data.ntc_beta_other; |
loopsva | 5:9655397ba539 | 52 | break; |
loopsva | 0:c0bdc272d5da | 53 | default: |
loopsva | 6:8e6bd0f9877b | 54 | beta = ntc_set_data.ntc_beta_2585; |
loopsva | 0:c0bdc272d5da | 55 | break; |
loopsva | 0:c0bdc272d5da | 56 | } |
loopsva | 6:8e6bd0f9877b | 57 | return beta; |
loopsva | 6:8e6bd0f9877b | 58 | } |
loopsva | 6:8e6bd0f9877b | 59 | |
loopsva | 6:8e6bd0f9877b | 60 | int NTC::get_series_res() { |
loopsva | 6:8e6bd0f9877b | 61 | return ntc_set_data.sres_res; |
loopsva | 6:8e6bd0f9877b | 62 | } |
loopsva | 6:8e6bd0f9877b | 63 | |
loopsva | 6:8e6bd0f9877b | 64 | float NTC::get_ntc_res_viaAD(uint16_t din) { |
loopsva | 6:8e6bd0f9877b | 65 | uint16_t ad = din; |
loopsva | 6:8e6bd0f9877b | 66 | if(din == 0) { |
loopsva | 6:8e6bd0f9877b | 67 | ad = NTC::read_ad_reg(); |
loopsva | 6:8e6bd0f9877b | 68 | } |
loopsva | 6:8e6bd0f9877b | 69 | float adv = ntc_set_data.vref / ntc_set_data.ad_resolution * (float)ad; |
loopsva | 6:8e6bd0f9877b | 70 | return (ntc_set_data.vref / ((ntc_set_data.vref - adv) / ntc_set_data.sres_res) - ntc_set_data.sres_res); |
loopsva | 6:8e6bd0f9877b | 71 | } |
loopsva | 6:8e6bd0f9877b | 72 | |
loopsva | 6:8e6bd0f9877b | 73 | float NTC::get_ntc_temp(int curve, uint16_t din) { |
loopsva | 6:8e6bd0f9877b | 74 | int beta = NTC::get_ntc_beta(curve); |
loopsva | 0:c0bdc272d5da | 75 | float ntc_res = 0.0f; |
loopsva | 0:c0bdc272d5da | 76 | if(din == 0) { |
loopsva | 0:c0bdc272d5da | 77 | ntc_res = NTC::get_ntc_res_viaAD(); |
loopsva | 0:c0bdc272d5da | 78 | } else { |
loopsva | 0:c0bdc272d5da | 79 | ntc_res = NTC::get_ntc_res_viaAD(din); |
loopsva | 0:c0bdc272d5da | 80 | } |
loopsva | 5:9655397ba539 | 81 | if(beta == 0) return -100.0f; |
loopsva | 0:c0bdc272d5da | 82 | return (beta / (log(ntc_res / (ntc_set_data.ntc_res * exp(-beta / 298.0f)))) - 273.0f); |
loopsva | 0:c0bdc272d5da | 83 | } |
loopsva | 0:c0bdc272d5da | 84 | |
loopsva | 6:8e6bd0f9877b | 85 |