200 lines
6.1 KiB
C
200 lines
6.1 KiB
C
/* Reflow Oven Controller
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*
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* Copyright (C) 2020 Mario Hüttel <mario.huettel@gmx.net>
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*
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* This file is part of the Reflow Oven Controller Project.
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*
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* The reflow oven controller is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* GDSII-Converter is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with the reflow oven controller project.
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* If not, see <http://www.gnu.org/licenses/>.
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*/
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/**
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* @file adc-meas.h
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*/
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#ifndef __ADCMEAS_H__
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#define __ADCMEAS_H__
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#include <stdbool.h>
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#include <stdint.h>
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#include <stm32/stm32f4xx.h>
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/*If this is changed, change DMA code to fit the channel assignment! */
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#define ADC_PT1000_PERIPH ADC3
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#define ADC_PT1000_DMA2_STREAM0_CHANNEL 2
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/**
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* @brief Moving average filter coefficient for PT1000 measurement
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*/
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#define ADC_PT1000_FILTER_WEIGHT 0.01f
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/**
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* @brief Moving average filter weight used for fast regaulation. This is used when the measured resistance
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* is more than @ref ADC_PT1000_FILTER_UNSTABLE_DIFF Ohms away from the current averaged value.
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*/
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#define ADC_PT1000_FILTER_WEIGHT_FAST 0.05
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/**
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* @brief Difference in Ohm between filter input and output that determines if the filter is stable or unstable.
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*/
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#define ADC_PT1000_FILTER_UNSTABLE_DIFF 20
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/**
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* @brief Sample count, the moving average filter has to be within @ref ADC_PT1000_FILTER_UNSTABLE_DIFF for the filter
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* to be considered stable
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*/
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#define ADC_PT1000_FILTER_STABLE_SAMPLE_COUNT 200
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/**
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* @brief ADC channel number of PT1000 sensor input
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*/
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#define ADC_PT1000_CHANNEL 2U
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/**
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* @brief GPIO Port the ADC converter for the PT1000 measurement is connected to
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*/
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#define ADC_PT1000_PORT GPIOA
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/**
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* @brief The clock enable mask of the RCC register for ADC_PT1000_PORT
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*/
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#define ADC_PT1000_PORT_RCC_MASK RCC_AHB1ENR_GPIOAEN
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/**
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* @brief The GPIO pin number the PT1000 analog voltage is connected to
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*/
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#define ADC_PT1000_PIN 2U
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/**
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* @brief The delay value programmed into the sample timer
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*/
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#define ADC_PT1000_SAMPLE_CNT_DELAY 1000U
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/**
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* @brief The amount of samples to take to prefilter the analog signal
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*/
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#define ADC_PT1000_DMA_AVG_SAMPLES 6U
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/**
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* @brief Lower value for valid input range for PT1000 measurement
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*
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* If the input of the PT1000 sensor is below this value, an error is thrown. This is used to disable the temperature control loop
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*/
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#define ADC_PT1000_LOWER_WATCHDOG 200U
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/**
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* @brief Upper value for valid input range for PT1000 measurement
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*
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* If the input of the PT1000 sensor is above this value, an error is thrown. This is used to disable the temperature control loop
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*/
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#define ADC_PT1000_UPPER_WATCHDOG 4000U
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/**
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* @brief Number of ADC samples the value has to be outside the Watchdog limit (@ref ADC_PT1000_UPPER_WATCHDOG and @ref ADC_PT1000_LOWER_WATCHDOG)
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* in order to produce a watchdog error
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*/
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#define ADC_PT1000_WATCHDOG_SAMPLE_COUNT 25U
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/**
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* @brief Conversion macro: ADC value to resistance
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*/
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#define ADC_TO_RES(adc) ((float)(adc) / 4096.0f * 2500.0f)
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#define RES_TO_ADC(res) ((float)(res) / 2500.0f * 4096.0f)
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/**
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* @brief This function sets up the ADC measurement fo the external PT1000 temperature sensor
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*
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* Used peripherals:
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* - Timer 2 for sampling control
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* - ADC1
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*
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* The filter weight \f$\alpha\f$ is configured for @ref ADC_PT1000_FILTER_WEIGHT
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*
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*/
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void adc_pt1000_setup_meas(void);
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/**
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* @brief Set moving average filter parameters
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*
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* The sampled resistance value is filtered with an exponential average filter
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* specified by following difference equation:
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*
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* \f$ y[n] = (1-\alpha)y[n-1] + \alpha x[n] \f$
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*
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* @param alpha
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*/
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void adc_pt1000_set_moving_average_filter_param(float alpha);
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/**
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* @brief Set the calibration data for the PT1000 measurement
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*
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* The resulting resistance reading is
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* \f$R_{corrected} = (1 + \sigma) R_{raw} + O\f$
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*
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* @param offset Offset \f$O\f$
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* @param sensitivity_deviation Sensitivity Deviation \f$\sigma\f$ after offset correction
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* @param active Calibration is active
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*/
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void adc_pt1000_set_resistance_calibration(float offset, float sensitivity_deviation, bool active);
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/**
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* @brief Get the state and values of the resistance calibration
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* @param offset Offset
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* @param sensitivity_deviation Sensitivity deviation
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* @param active Active state of the correction
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*/
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void adc_pt1000_get_resistance_calibration(float *offset, float *sensitivity_deviation, bool *active);
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/**
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* @brief Get the current resistance value
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*
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* If the resistance calibration is enabled, this function applies the calculations of the raw resistance reading and
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* returns the corrected value.
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*
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* If an ADC error is set, the status is negative. The status is 2 during the first measurements with a given filter setting. Technically, the resistance value is
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* correct but the filter is not stable yet.
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*
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* @param[out] resistance Resistance output in Ohms
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* @return Status
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*/
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int adc_pt1000_get_current_resistance(float *resistance);
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/**
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* @brief Stream the raw ADC data to an array in memory.
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* @param adc_array Array to stream data to
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* @param length Amount of data points to be measured
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* @param flag_to_set This flag is set to 1 once the data has been measured and is transferred. A negative value indicates an error
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* @return 0 if measurement could be started
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*/
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int adc_pt1000_stream_raw_value_to_memory(volatile float *adc_array, uint32_t length, volatile int *flag_to_set);
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/**
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* @brief Convert an array of raw adc values to resistance values
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*
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* In case \p resistance_dest is NULL, the conversion is done inplace in the
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* \p raw_source array.
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*
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* @param resistance_dest Destination. Maybe NULL.
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* @param raw_source Source array
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* @param count Number of values to convert
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*/
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void adc_pt1000_convert_raw_value_array_to_resistance(float *resistance_dest, float *raw_source, uint32_t count);
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/**
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* @brief Disable the PT1000 measurement
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*/
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void adc_pt1000_disable(void);
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#endif // __ADCMEAS_H__
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